Copyright © University of Cambridge. All rights reserved.
Three frogs came in through the kitchen door
Said one to the others "let's explore"
The frogs hopped in and onto the table.
They sat in a line and admired the view - the red frog on the left the green in the middle and the blue frog on the right.
In their excitement they hopped over each other - one frog hopping randomly over any adjacent frog.
After 999 hops they stopped!
Why I do not know - perhaps they were exhausted.
Is it possible, after their 999 hops, for them to have ended up in the position in which they started?