QZ qz thoughts
a blog from Eli the Bearded
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Covid-19, Day 244

Latest numbers: dispensing with the state numbers now. US overall now over six million cases and more than 183,000 deaths. As "back to school" kicks in, new outbreaks, particularly at colleges are appearing. World wide cases are over 25 million and deaths stand over 844,000. In recent weeks some states have started to scale back testing, following Federal guidance that seems based on Trump's fewer tests will mean fewer cases fantasy. Rapid testing is still a burden to find in the US.

Increasingly I'm seeing bars and restaurants put in outdoor seating, using the "parklet" model San Francisco has. Basically this is the conversion of on-street parking to protected space for people.

Three parklets for outdoor seating

Here three separate businesses have three parklets at one intersection. One is simply metal barriers for now. If it follows the practice seen elsehwere, the walled wood platform will be there soon.

Prior to covid-19 very few parklets were all wood construction, and some had very artistic designs. Consider the "Deepistan National Parklet" created in 2011, with a topiary dinosaur.

The triceratops topiary at Deepistan Parklet

When it was created, Deepistan National Park(let) was the only parklet sponsored / in front of a residence.

But now rapid and cheap is the name of the game, and basic wood boxes are springing up around the city. This is all fine and well on good days, but rainy weather will be coming, and right now San Francisco is in the midsts of it's longest ever streak of "Spare the Air" days, where certain activities are discouraged and some are illegal due to bad air quality. (Discouraged: driving, at risk people spending time outdoors; illegal: wood fires including beach bonfiles.) The air is so bad because of blown in smoke from wildfires around the state.

It's a bad year for wildfires. The current batch was started by a rare series of August lightning strikes, months after the last rain. Many small fires started and grew until they combined into a few huge fires. Two out of the three largest wildfires in California history were burning simultaneously, and Covid-19 hindered both response and shelter options for people evacuated.

There have been a few days that the smoke layer sitting on the city has been very unpleasant for me. As I've gotten older, wood smoke causes my nasal passages and lungs more and more distress. When mask wearing started for Covid-19, I first began using my "Vog" brand N-95 mask which I had purchased for dealing with wildfire smoke in the city in previous years.

But more distressing than than the disruption of the disease or the suffocating smoke has been the politics. Trump's rejection of reality and outright stoking of racism, his obvious attempts to thwart voting, his destruction of norms and the US Postal Service, all of that is becoming a dispiriting drain on my mental health. Trump didn't accept the election results when he won, I have no illusions he'll accept a loss this time. And I have no stomach for imagining how it will shake out.

slowcat.c and signature.c

A discussion in the Usenet group comp.sys.raspberry-pi about browsers turned to ASCII art when I brought up concerns about showing ASCII art in web pages (based on the recent notint screenshots here). And that discussion had one Charlie Gibbs reminisce about the "Andalusian Video Snail".

I found the file for him at https://grox.net/misc/vt/ — it's an ASCII art animation with VT100 escape codes so viewing it is tricky. Those animations are typically highly dependent on viewing on slow terminals, and modern hardware is anything but a slow terminal.

At grox.net there is also a slowcat.c which easily compiles. That code is essentially a loop of getchar();nanosleep();putchar(); to delay output. It worked okay for a few videos I tried, but the snails did not look so good. And it would not slow down STDIN, which would be handy for a program I wrote (more later).

So the biggest problem with the Grox slowcat.c is while it adds delays, it doesn't disable output buffering, so output ends up being large chunks showed without delay and then a delay for the next large chunk. That doesn't suit that particular animation well. Other problems include a "cat" that only shows exactly one file instead of arbitrary numbers, an awkward interface for delays (how many nanoseconds do I really want? and why does the code use usecs for presumably ╬╝seconds), and arg parsing oddness.

I decided to rewrite slowcat. I disabled buffering, switched to usleep(), employ getopt() and an arbitrary number of files, and added a option to have the program calculate a delay to emulate a particular baud rate, which is how terminal speeds were measured when these were written. Quite likely a baud of 1200 or 9600 was assumed by the animator. Baud is a measure of bits per second, so 9600 works out to 150 characters per second, or about 13 seconds for an 80x24 terminal screen. When I test time slocat -b 9600 snails.tv takes 3m33.23s while time cat snails.tv takes 0.47s. On my system stty tells me 38400 baud, which would be 4 times faster, but since it actually runs 453(ish) times faster, the baud equivalent is closer to 4,500,000 than 38,400. For most purposes, that faster speed is much appreciated.

So back to signature.c, by which I mean this program:

------                                         /* gcc signature.c -lm */
main(){int i,j,k,l;for(i=-12;i<13;i++,printf("\033[H")){for(l=61968*457+
p(10):0;}}puts("Elijah ");}p(int m){printf("%c",m);}

I use it in place of a .signature on select Usenet posts. I wrote it approximately 1995. Over the years, it's been used perhaps one or two dozen times, and I have made at least five variants with different email addresses, each of which has been reformated to have the lines the same length.

(An aside on .signatures: I have never used a proper .signature, that is to say a block of standard text appeneded automatically to the end of my posts or email. I have always done it manually, and, for Usenet posts, 99.9% of them are unique entries composed for that particular post. I have about 30 programs, most in Perl, that I have used and reused from time to time. Since I don't consider them true signatures, and do consider them part of the post, I do not use proper signature cut lines — dash dash space on a line by itself — which annoys some people, sometimes.)

The origins of that program are interesting. The program came to me in a dream where I visualized an ASCII art movie of cross-sections of a sphere that changes "color" closer to the core. The colors are represented by the characters in the string ".,:;iIJYVSOM" and the code uses some basic IOCCC obfuscation tricks, like using C arrays backwards: (offset)["array to index"], but is mostly pretty readable once reformatted. The use of +++ is very classic me, since I enjoy testing how far I can push a parser to accept the same character over and over. My extreme is perhaps this Perl one:

sub S(){@s=caller($/);$s[3]=~s s\w+:+ss&&print$s[3].q. .}$/=$^=~s/\S+/\n/;
$_="Just (eli) Another (the) Perl (bearded) Hacker";sub s($){eval$_[0];$/}
while(s&&&&& &s(qq&sub$^&.$&.q&{\&S}&)&& &{$&}&&s&&&){$/}$\=$^;print"\b,";

Five ampersands in a row, then a space because the parser choked on ampersand six. s&&& runs a substitution using the previous regexp, so the RE field between s& and the middle & is empty and replaces the match with an empty string, the middle & and third &. If that succeeds (&&) call subroutine s: &s. I needed a space on either side of the && and operator as a hint to the parser about what's going on, and I choose to go with after to get five in a row. Then I squeeze as many extra ampersands as I can in the rest of that line. I'm pleased to say that since I wrote that, the Perl parser has improved to the point that the six ampersand in a row version now works: a fragment like (s&&&&&&s( is either a nightmare or a wonderous sight depending on your tastes.

But I digress. The dream version of sphere.c did not include the use of the number 28319377 to represent "Elijah" printed on every frame, I added that when I decided that sphere.c should become signature.c. It's obfuscated enough that the average schmoe won't be able to change it, but could perhaps remove it.

But like those other ASCII art movies, signature suffered from the speed-up of terminals. The visualization cannot be appreciated at such lightning rates. The fix to have slowcat work on STDIN was added with my signature program in mind: signature | slowcat -b 9600

My slowcat and the latest version of signature.c, now fixed to have a more circular sphere, are available at github, along with various animations (the animations from grox.net and textfiles.com).


One of the better Tetris clones for the Unix terminal enviornment is TINT, a recursive acryonym for TINT Is Not Tetris. (There is more than one Tetris clone by that name, apparently obvious joke is obvious.) Clean C code, good responsiveness, color output (curses "text UI").

I bring all that up, because a couple of years ago I had a vision for changing some of the rules of Tetris to see how the game would play. To do that, I found an open source version of the game and started hacking on it. The one I first found was the version in the BSD Games package. The resulting new game I called Eastris. It showed potential, but the game was not responsive at speed. Digging I found the original code was based on an IOCCC winner. So the original source was more about size of code than playability.

Eastris screenshot

Score: 9                   ww                   ww
Status: 11 - 0             ww                   ww
                           ww                   ww
                           ww                   ww
                           ww                   ww
                           ww                   ww
                           ww    wwww           ww
                           ww  wwww             ww
                           ww                   ww
                           ww                   ww
                           ww                   ww
                           ww                   ww
                           ww                   ww
                           ww                   ww
                           ww                   ww
                           wwww ww ww      ww   ww
                           wwwwwwwwwwwwwwwwwww  ww
                           ww  ww ww  wwwwwwww  ww
                           ww  wwwwwwwwwwwwwwwwwww
                           wwwwwwwwwwwwww  wwww ww

   j - left   k - rotate   l - right   <space> - drop   p - pause   q - quit

Then I found TINT, and it plays better and has nicer code. My derivative of that I'm calling NOTINT, for "Not TINT". Besides the "easytris" mode, I've modified it to have several other play options. But maybe a discription of what easytris is would be good now.

Standard Tetris has a blocks that fall and stack. You complete rows to clear the board area, and you strive to never run out of space at the top. Easytris has all those same features. It even has the same shapes. What it doesn't have, and what made me call it "easy," is very random piece distribution. Instead you get mostly the same peice over and over again for a while, and then it changes to a random new piece to get over and over again. The way it is supposed to be easy: you have a good idea of what's coming, next, and after that, and after that. So you can plan your moves long in advance.

In practice, most of the pieces are pretty difficult to use to clear the board when you get 25 of the next 30 pieces all the same. Only the 1x4 piece is really easy. The 2x2 square piece seems simple, but is extremely unforgiving of mistakes. The T shape and the two variants of L shape are tricky, but with care can be used to clean up a board. The two S-jog shapes can maintain an equalibrium, but cannot really clean things up. Playing easytris really sharpened my Tetris skills, even if I did get bored after a while.

One that I started to notice playing a lot of tint style Tetris is that scoring is dominated by how far you drop pieces. It's much more important than clearing lines to the score. So I started adding new play modes to notint.

First was "zen mode" where the game speed never changes (unless you ask it to) and the scoring is 100% about lines cleared. Next I added a "speed mode" that makes scoring a function of lines cleared over time, but to be honest, I'm not very satisfied with that scoring and I may rework it.

After that I added "challenge mode". This has makes levels mean something different. Each level starts with a set of blocks that you have to clear. Those blocks are all incomplete lines, some levels have random patterns and some have predetermined patterns. Some levels have traditional random pieces and some have "easytris" inspired preferred pieces. Whatever the pattern or drop ratios, once you clear all the challenge blocks away, the board resets for the next level.

Notint in easytris mode screenshot

 Your level: 6             <>                    <>            STATISTICS
 Full lines: 138           <>                    <>
Blocks togo: 50            <>      YYYYYY        <>       MMMMMM        -    30
  Score  2536              <>        YY          <>       MM
                           <>                    <>           RRRRRRRR  -    30
                           <>    YY  YY          <>
    H E L P                <>  YYYYYYYYYY        <>       WWWWWW        -    47
                           <>      YYYYBBBB    YY<>           WW
 p: Pause                  <>      YYYYBBBB  YYYY<>               GGGG  -    26
 j: Left                   <>YYYY  YYYYYYYYCCCCYY<>             GGGG
 l: Right                  <>    YYYYYYYYYYYYMM  <>       CCCC          -    18
 k: Rotate                 <>YYYYYYYY  YYYYYYMMMM<>         CCCC
 s: Draw next              <>  YYYYYYYYYYYYYYYYYY<>               BBBB  -    27
 d: Toggle lines           <>YYYYYYYYYYYY  YYYYYY<>               BBBB
 a: Advance level          <>  YYYYYYYYYYYYYYYYYY<>       YYYYYY        -   184
 q: Quit                   <>YYYY  YYYYYYYYYYYYYY<>         YY
  SPACE: Drop              <>YYYYYYYYYYYYYYYY  YY<>       ---------------------
                           <>YYYYYYYY  WWWWWWYYYY<>       Sum          :    362
   Next:                   <>YYYYYYYYYYYYYYYYYY  <>
                           <>++  ++YY++YY++YY++GG<>       Challenge    :   5
                           <><><><><><><><><><><><>       Other blocks : 110

This has been my focus of late. All of the predetermined patterns I have been able to clear in random piece drop mode, but some are really hard unless you get lucky with your drops. After a while, I started to feel those were unfair, which is why I added less-random piece distributions. The really hard ones were the tall single-spaced bars and the two (one tall, one short) checkerboard patterns. Above, I'm failing pretty hard on one of those checkerboard levels with just a single challenge row left to clear.

NOTINT source at github.