Drawing the Twitter logo in QBasic

DEFINT A-Z
SCREEN 7
DO
  READ x, y, r
  c = 9 - SGN(SGN(r) + 1) * 9
  CIRCLE (x, y), ABS(r), 15, , , 1
  PAINT STEP(0, 0), 14, 15
  PAINT STEP(0, 0), c, 15
  CIRCLE STEP(0, 0), ABS(r), c, , , 1
LOOP UNTIL x = 185
DATA 148, 83, -56, 120, 79, 51, 148, 103, -19, 136, 89, 20, 140, 90, -19
DATA 131, 73, 19, 140, 74, -19, 166, 89, -19, 165, 33, 51, 197, 64, -17
DATA 204, 55, 19, 193, 57, -19, 186, 18, 51, 185, 81, -19