The teachpack provides functions for creating and manipulating an arrow GUI. We recommend using 2htdp/universe instead.
A modelT is a function that accepts and ignores two arguments.
Reads out the current state of the message field.
Displays s in the message field.
Connects four controllers with the four directions in the arrow window.
Now click on the four arrows. The message field contains the current direction, the print-out the prior contents of the message field.