Abstract: A device for defining the profile of a basketball foul lane and key on a surface such as asphalt or concrete. The device is comprised of a plurality of panels wherein each panel has opposing side walls which define a section of the profile therebetween. Connecting ribs are disposed between the side walls for the purpose of connecting the side walls. The plurality of panels is arrangeable so that the sections of the profile align to form the profile of a basketball foul lane and key. The device may be conveniently supplied and sold as an apparatus which includes the device, tape to temporarily attach the device to the solid surface, paint to paint the profile exposed on the surface by the device and a plumb bob to properly align the device on the surface.