16 box "\s-4SPARC stack\s+4" ht .2
17 box "\s-4EM stack\s+4" ht .1
18 box "\s-4SPARC stack\s+4" ht .1
19 box "\s-4EM stack\s+4" ht .1
20 box "\s-4free\s+4" ht .2
21 box "\s-4SPARC stack\s+4" ht .1
30 box invis "regular \(UX memory layout"
32 box invis "memory layout for EM"