Playground
The playground at Wayside school is symbolic of childhood innocence, naivete, and exuberance. In "Mr. Poop," for example, the kids play at the playground with less-than-ideal toys, much to the chagrin of Louis, who represents the adults. Despite the poor toys they have to play with, the kids don't care and have quite a bit of fun at the playground.
Cow
The cows scattered across the school are symbolic of the kids' zaniness and their fun nature. Having cows in the school is absurd; the kids love having the cows as well. But this truth remains: cows don't belong near a school, much less inside a school. This incongruency creates a tremendous amount of humor and emphasizes how unreal and fantastical the book is.
The pickle-like stone
The Pickle-Like Stone is symbolic of the hold that adults (particularly Doctor Pickle) has over the kids in the school. The Pickle-Like Stone is, in the context of the story, a device which Dr. Pickle uses to hypnotize the kids to do what he - and other adults - want them to do. This gives depth to Dr. Pickle's character and the kids' character. It also adds depth and humor to the book.
Things that don't make sense
A common motif in the novel is things that don't make sense, like the color coded elevator that only goes one direction. This strange and unexpected situation, quite simply, is used to add humor the book. It also illuminates to readers how strange the characters in the book are: the people who built the elevator and the people who thought nothing of using the elevator.
Confusing pet names
A minor motif in the novel is children's pets having strange and oftentimes confusing names. Sachar does this to infuse comedy into his novel and does this as a way to underscore how zany and funny the kids in the class are. Strange and zany things, after all, are a trademark of Sachar's series.
