A cartridge includes a first member that prevents a first signal, having first intensity, from passing entirely therethrough, wherein one portion of the first signal has a second intensity. A second member either prevents a second signal having a third intensity from entirely passing therethrough, or allows one first portion of the second signal to pass therethrough. The first portion of the second signal has a fourth intensity. The third intensity is greater than the fourth intensity. The first intensity is greater than the second intensity. A third member either prevents the second signal from passing entirely therethrough, or allows either the first portion of the second signal or one second portion of the second signal to pass therethrough. The second portion of the second signal has a fifth intensity. The third intensity is greater than the fifth intensity. An intermediate portion is formed between the second and third member.