wm geometry . 500x500
canvas .c -bg white
pack .c -expand 1 -fill both
.c create oval 230 230 270 270 -fill red
array set direction {
n 0
s 0
e 0
w 0
}
set delta 3
bind . <KeyPress-Up> {set direction(n) 1}
bind . <KeyPress-Down> {set direction(s) 1}
bind . <KeyPress-Right> {set direction(e) 1}
bind . <KeyPress-Left> {set direction(w) 1}
bind . <KeyRelease-Up> {set direction(n) 0}
bind . <KeyRelease-Down> {set direction(s) 0}
bind . <KeyRelease-Right> {set direction(e) 0}
bind . <KeyRelease-Left> {set direction(w) 0}
proc move {} {
global direction delta
if {$direction(n)} {.c move 1 0 -$delta}
if {$direction(s)} {.c move 1 0 +$delta}
if {$direction(e)} {.c move 1 +$delta 0}
if {$direction(w)} {.c move 1 -$delta 0}
after 10 move
}
move