See the FAQ or the WIKI or use the Forum Search...
And don't forget to switch on your brain before doing so.

i made a sim on how to use pipe and with aray zoom in and use a 1 square brush put 1 dot aray the behind it put 1 dot of metal and then behind the metal but 1 dot battery (the laser will fire out the opposite direction u made the line of materials including diagonal)

hope this helps

ps check out my flamethrower contest if u win ull get ur name posted in a topic so 1 entire topic on your name