modified:
--------
panel.bmp    (up+down+airzone)
hosi4.bmp    (orange) |
hosi3.bmp    (orange) | don't seem to be visible because of color limitation
hosi2.bmp    (orange) |
hosi1.bmp    (orange) |
gameover.bmp (around for visibility)
airshort.bmp (button)
airminus.bmp (button)

redone:
------
mainback.bmp    (less basic)
blockX4.bmp     (to show state)
blockX2.bmp     (to show state)
blockX1.bmp     (to show state)
blockX.bmp      (to match X1, X2 & X4)
hosi5.bmp       (cuttiest)
yellowblock.bmp (for multi-blocks)
redblock.bmp    (for multi-blocks)
greenblock.bmp  (for multi-blocks)
clearblock.bmp  (for multi-blocks)
blueblock.bmp   (for multi-blocks)