Width% = 320
      Height% = 240

      VDU 23,22,Width%;Height%;8,16,16,128
      *DISPLAY Pentagon.bmp
      OFF

      DIM hist%(Width%-1, Height%-1)

      rs = 2 * SQR(Width%^2 + Height%^2) / Height% : REM Radial step
      ts = PI / Width% : REM Angular step
      h% = Height% / 2

      REM Hough transform:
      FOR y% = 0 TO Height%-1
        FOR x% = 0 TO Width%-1
          IF TINT(x%*2, y%*2) = 0 THEN
            FOR t% = 0 TO Width%-1
              th = t% * ts
              r% = (x%*COS(th) + y%*SIN(th)) / rs + h% + 0.5
              hist%(t%,r%) += 1
            NEXT
          ENDIF
        NEXT
      NEXT y%

      REM Find max:
      max% = 0
      FOR y% = 0 TO Height%-1
        FOR x% = 0 TO Width%-1
          IF hist%(x%,y%) > max% max% = hist%(x%,y%)
        NEXT
      NEXT y%

      REM Plot:
      GCOL 1
      FOR y% = 0 TO Height%-1
        FOR x% = 0 TO Width%-1
          c% = 255 * hist%(x%,y%) / max%
          COLOUR 1, c%, c%, c%
          LINE x%*2,y%*2,x%*2,y%*2
        NEXT
      NEXT y%

      REPEAT
        WAIT 1
      UNTIL FALSE