Sierpinski Triangle 10 Liner

Sierpinski10Liner is a simple Sinclair ZX81 BASIC language implementation of the Sierpiński triangle fractal construction using the chaos game algorithm.

The program is made up of 10 (actually 9, the last is just a REMark statement) BASIC lines with one statement per line and is the improved version of a similar program I made some years ago. It should run on any un-expanded (1KB RAM) or expanded ZX81 computer or clone.

Sierpinski10Liner is my entry to the BASIC 10-Liner Contest 2020, SCHAU category.

1 LET X=30    
2 LET Y=40    
3 LET K=INT (RND*3)    
4 LET A=30*K    
5 LET B=40*(K=1)    
6 LET X=INT ((X+A)/2)    
7 LET Y=INT ((Y+B)/2)    
8 PLOT X,Y    
9 GOTO 3   
10 REM MARCO'S RETROBITS 2020