Teacher to student groups (4 people) Group 1 replica watch crafting and give each group the simulated fabrication intended to the members of the group told time.
Teachers give students the same group (4 people), inventor of the first group of replica watches and replica watches for each group to devise a set time. Then members of the group told the Times.
The teacher after the original (4) artificial simulation clock, each group, and each group 1 led watches artificial simulation on the timer. Then the group members tell the time.