Press 1 to choose the left set. Press 2 to choose the right set. Press space (or click the green flag) to reset. The numbers to the left are colors of the left set and the right set (use in the "set pen color block", no, not the number one, the one with the square, just put a variable in the square).
Hacked block "for each" thanks to @MegaApuTurkUltra .
