global c = 0

$WheelDown::            ; Down/Sleep/Up usage.
key := DownSeqkeys("F2","F3","F4","F5")
send {%key% Down}
sleep, 20
send {%key% Up}
return

$WheelUp::            ; Down/Sleep/Up usage.
key := UpSeqkeys("F2","F3","F4","F5")
send {%key% Down}
sleep, 20
send {%key% Up}
return


UpSeqkeys(k1,k2,k3,k4){   ; 4 keys rotation, 8 second reset.
    static s:=0, t:=8000
    (A_TickCount-s<=t && c>1) ? c-=1 : c:=4, s:=A_TickCount
    Return k%c%
}
DownSeqkeys(k1,k2,k3,k4){   ; 4 keys rotation, 8 second reset.
    static s:=0, t:=8000
    (A_TickCount-s<=t && c<4) ? c+=1 : c:=1, s:=A_TickCount
    Return k%c%
}