A method of interacting with a computing device via one or more inking instruments to generate digital ink may include the steps of emitting light from a light emitting device to an inking instrument, receiving first user inputs from the inking instrument, and identifying the inking instrument based on sensed light reflected from the inking instrument. Another method may include the steps of simultaneously detecting first user inputs from a first inking instrument and second user inputs from a second inking instrument by receiving first light emitted from the first inking instrument and second light emitted from a second inking instrument that each have one or more identifying characteristics, identifying the inking instrument based on their identifying characteristics, and generating corresponding digital ink. These methods may be implemented via computer-executable instructions and may be used with a horizontally-placed display, tablet-based laptop computers, and passive or active digital inking instruments.