We are all accustomed to supposing that all change takes place along the linear time axis: from past to present to future. The present is an accrual of the past and is different from it. The future will accrue from the present on and be different yet. That an orthogonal or right-angle time axis could exist, a lateral domain in which change takes place - processes occurring sideways in reality, so to speak - this is almost impossible to imagine. How would we perceive such lateral changes? What would we experience? What clues - if we are trying to test this bizarre theory - should we be on the alert for?