sprite channel allocations
1 back wall
2 - 12 navigation
13-16 1 bit interface corner masks
18 backdrop
19 QuickTime
20-99 usable by games and activities (80 free sprites)

100-103 4 x interface corner 1 bit masks

104 map
105 exit door
106 glinda's mirror
107 medallion
108-116 jewels
118 sparkle for jewels ("add pin" ink)
119 cursor
120 black rectangle for hiding everything