80386 machine code, IBM PC DOS, 38 bytes
hex:
B0 13 CD 10 68 00 A0 1F 66 C7 06 00 00 28 2C 24
00 66 C7 06 40 01 2C 30 34 00 66 C7 06 80 02 24
34 20 00 CD 16 C3
asm:
mov al,13h
int 10h ; initialize vga 13h mode (320x200x256 colors)
push 0a000h
pop ds ; push video buffer address to ds
mov dword ptr ds:0, 242c28h ; print 3 pixels
mov dword ptr ds:320, 34302ch ; print 3 pixels
mov dword ptr ds:640, 203424h ; print 3 pixels
int 16h ; wait for any keypress
ret #; exit to os
scaled output from dosbox: