get 0 4
put 0 4
get 0 4
after x=dom`x++: x = 0, dom`x = 1
get 4 8
put 4 8
get 4 8
after y=++dom`y: y = 1, dom`y = 1
get 0 4
put 0 4
get 0 4
after x=dom`x--: x = 1, dom`x = 0
get 4 8
put 4 8
get 4 8
after y=--dom`y: y = 0, dom`y = 0