Box-256 Assembly - BIG SQUARE II
8 instructions

My smallest solution to the Big Square II challenge is 8 lines of code. There's a simple loop which cycles through a table of 8 pixel locations.

; Big Square II in 0x08h instructions
; John Metcalf

PIX @18 002 000
ADD @16 @18 @18
MOV @18 @20 001
MOV @19 @18 008
FLP @16 @17 001
JMP @00 001 010
011 031 021 032
0D3 01D 0E3 01E