_________________________________________ / \ / +------+ \ | | PCE | | | +------+ | | | | | | +------+ 10 +------+ | CE1 ****| PE 1 | ----- R1 ---- R2 ------- | PE 2 |**** CE2 | +------+ | \ | +------+ | | | \2 | | | | \ | | | +------+ | \ | +------+ | CE3 ****| PE 3 | ----- R3 ---- R4 ------- | PE 4 |**** CE4 | +------+ +------+ | | | \ / \_________________________________________/