Jukka-Pekka Ikaheimonen, Juha Saukkola, and Rozberk Omniist solved the packing problem:
AABCDEEE
AABCDDEE
ABBCCDDD
BBFFCGGG
FFFHGGII
JJJHHIIK
LLJJHIKK
LLLJHIKK

Only Axiom discovered the solution to the prefix problem:  MONOPOLY.  That's right, monopoly.  Now say polopony.  Scott Purdy suggested the solutions prepost and pro-con.