Try to control three lights with $2$ buttons. The states of the lights are shown as:

LD

SFC

Initial State:

Press Button Light $1$ on Button$1->$X$02$s later Button $2->$X$1$ Light $2$on Light $1->$Y$02$s later Light $2->$Y$1$

Light $3->$Y$2$ Light $3$ on Press stop button to end the process