The day was February 14. The clock read 16:59 when the operator answered author Ehud Schori's phone call, but it was just after 17:04 when he heard the voice of the man he wanted to speak with. He had to wait five minutes. Schori would later discover that he actually waited fourteen hedgehogs - he can still remember their thorns. He drew every one of them. The drawing above represents the relationship between objective and subjective time; the hedgehogs are actually subjective time units. Schori visualizes the intricacies of time measurement through the drawings contained within these pages. Learn the subtle differences between objective and subjective time through seventy-four visuals that explore creative methods of time measurement.