In Pokemon crystal version where do i find the missing piece from the power plant in cerulean city?

go into the gym and a guy might bump into you, either way, just go to the square of water in the middle and press A!!!!!!!!

I tried this and all it said was, "do you want to surf?"

--Yeah it does ask you to surf but since the square of water is 4 units, press A on the top left one. u can surf or u can just walk around to it and press A. =P