; color loop with the stack
  LDX #$00
  LDY #$00
firstloop:
  TXA
  STA $0200,Y
  PHA
  INX
  INY
  CPY #$10
  BNE firstloop ;loop until Y is $10
secondloop:
  PLA
  STA $0200,Y
  INY
  CPY #$20      ;loop until Y is $20
  BNE secondloop