I wrote this a few years ago.
Picross or Nonogram is a puzzle game where you paint by the numbers. Each row and column are given numbers based on the original image The rules are explained here with a great example of how it works
I made a spin of the game in that instead of having one board you have 5 boards each representing a different color red, blue, yellow, white, and black.
Say if there is a 1 in the red, blue, and black boards. The resulting color the user sees is dark purple. You can also create your own puzzles (given that you have RMXP).
This was coded in Ruby using RPG Maker XP