See also: part 1, part 2, part 3 and part 4.

Special thanks to Jason Pittman for mentioning this year’s challenge in a comment…

Logiker is at it again, with a 2023 retro-programming Christmas challenge:

???? Vintage Computing Christmas Challenge (VC³) 2023 ???? – Logiker

This year, the pattern looks like this:

   *     *     *
  * *   * *   * *
 *   * *   * *   *
*     *     *     *
 *   * *   * *   *
  * *   * *   * *
   *     *     *
  * *   * *   * *
 *   * *   * *   *
*     *     *     *
 *   * *   * *   *
  * *   * *   * *
   *     *     *
  * *   * *   * *
 *   * *   * *   *
*     *     *     *
 *   * *   * *   *
  * *   * *   * *
   *     *     *

This image is 19×19, so while it will fit on a Radio Shack Color Computer 1/2 screen width-wise, it’s a bit too tall to fit height-wise. The challenge allows for it to scroll off the screen, which is something we had to do for past challenges.

I can think of a number of ways to approach this.

The pattern is made up of only four unique lines, so you could print them A B C D B C A B C D and so on. There’s probably a simple way to do that with a FOR/NEXT loop and an array of those four lines.

10 CLS
50 A$(0)="   *     *     *
60 A$(1)="  * *   * *   * *
70 A$(2)=" *   * *   * *   *
80 A$(3)="*     *     *     *
90 FOR I=1 TO 3
100 FOR A=0 TO 3:PRINT A$(A):NEXT
110 FOR A=2 TO 1 STEP-1:PRINT A$(A):NEXT
120 NEXT
130 PRINT A$(0)
333 GOTO 333

If we had a larger screen (like the 40 or 80 column screens on the Color Computer 3), we could use LOCATE x,y to plot the pattern using some line drawing type math.

We could try the RLE (run length encoding) compression from past years to see if we could compress it down to spaces and characters.

We could try using math to figure out a pattern.

These all seem fun.

I hope to find some time to experiment. I don’t plan to “enter,” since one of the asks for the challenge is to not share your work until after the challenge ends.

More to come…