Disclosed are multifunctional sulfur-containing polymers that are the reaction products of a sulfur-containing diol, a polyol containing at least three hydroxyl groups per polyol molecule, and an aldehyde, a ketone, or a combination thereof. A plurality of nested control loops may employ cascaded proportional controllers to provide desired control of a pulse width modulation block to control an inverter that supplies AC power to the load. The accessed information content is retrieved and adapted for presentation for the electronic device. The laser pick-up also includes a photodetector affixed to the musical instrument adjacent the laser diode. The iron golf club head preferably has high moments of inertia Izz and Ixx.