XMAS Challenge 2025

Author: Frank Breuer
Category: Christmas Challenge
System:   ZX Spectrum ZX80
Language: Sinclair BASIC
Len source code: 311bytes

Instructions:
use FUSE-Emulator
open .tap or .z80-File
type in RUN Command
press ENTER

Description:

each sector of the snowflake is 8x8 pixels wide
so we can store the position of the "flakes" as bitpattern in 8 bytes
then we iterate over the bits in each byte and print for each bit set a flake in all 4 sectors of the flake

since Sinclair BASIC lacks built-in bit-operations, a graphical approach is used
data is poked into screen memory and tested if pixel is set or not, using a built-in function

in the end we draw the horizontal and vertical line,using the existing/running loops
its a little bit redundant, but gets the job done

Comments:
program length is calculated with "PRINT 65536-USR 7962"-method. dont know, if this is the best or correct way