A semiconductor structure includes a first semiconductor layer, an active layer, a second semiconductor layer, a first optical symmetric layer, a metallic layer, and a second optical symmetric layer stacked in that sequence. Among other things, the terpolymers provide for improved bake technologies. The digital data processor, further, and monitors the sensing device to identify user actions in response to those sounds and drives the audio output device to effect still further sounds based on those actions. Still further, transaction card systems are provided comprising a case or housing for holding andor storing foldable transaction cards therein, such as foldable transaction cards having a dimension, such as a length dimension or a width dimension, that is smaller than traditionall-sized transaction cards.