Cause if they rolled forwards, they would still be in the boat.
Roll a penny down a hill.
A chicken and an egg are lying in bed. The chicken is leaning against the headboard smoking a cigarette with a satisfied smile on its face. The egg, looking a bit ticked off, grabs the sheet, rolls over and says ... "Well, I guess we finally answered THAT question!"
Cause he can only move diagonally
Cause Jimmy had a frog stapled to his face.
They threw a cigarette overboard, and made the boat a cigarette lighter
They throw a boat at it.
Because if they fell foward, they would still be on the boat.
Because if they went forward they'd fall in the boat.
