\r
3 <model> "x" set\r
"x" get [ 2 * ] <arrow> dup "z" set\r
-[ 1+ ] <arrow> "y" set\r
+[ 1 + ] <arrow> "y" set\r
[ ] [ "y" get activate-model ] unit-test\r
[ t ] [ "z" get "x" get connections>> memq? ] unit-test\r
[ 7 ] [ "y" get value>> ] unit-test\r