For the Jack and Jill Hill, go here.
Jack and Jill is an English nursery rhyme about a boy and a girl who fell off a hill.
Appearance and Personality
"Jack and Jill went up that hill, for a supposed pail of water. [..] Jack fell down, broke his crown, 'cause Jill pushed him - but no one caught her!"
When Alex asks Mother Goose why Jack pushed Jill, she starts to rhyme:
"Jack is nimble, Jack is quick- but Jack can be such a- "
- TLOS II, ch 7, p. 100