#MaxThreadsPerHotkey 3
F12::  ; Win+Z hotkey (change this hotkey to suit your preferences).
#MaxThreadsPerHotkey 1
if KeepWinZRunning  ; This means an underlying thread is already running the loop below.
{
    KeepWinZRunning := false  ; Signal that thread's loop to stop.
    return  ; End this thread so that the one underneath will resume and see the change made by the line above.
}
; Otherwise:
KeepWinZRunning := true
Loop
{
    ; The next four lines are the action you want to repeat (update them to suit your preferences):
    Send {Numpad0 down}
    Sleep 100
    Send {Numpad0 up}
    
    ; But leave the rest below unchanged.
    if not KeepWinZRunning  ; The user signaled the loop to stop by pressing Win-Z again.
        break  ; Break out of this loop.
}
KeepWinZRunning := false  ; Reset in preparation for the next press of this hotkey.
return