Analyze the problem. Dr. Peter Venkman (Listen. Focus on WHAT. Understand IT!). Formulate a model. Dr. Raymond Stantz (Talk. Focus on HOW. Develop a PLAN. PLAN it!). Solve the problem. Dr. Egon Spengler. (Code IT! Or "Just DO it". Implement it on the computer using some software tool or programming language. NetLogo, Excel, Vensim, After Effects, Flash, Photoshop, C++).
You can use the pick whip to link rotation values between layers to animate the hands on a clock - as the hour hand moves from hour to hour, the minute hand rotates the full circumference of the clock face. Import or create two long, narrow solid-color layers: an hour hand and a minute hand. Set the anchor points at the ends of the layers. Move the layers so that the anchor points are at the center of the composition. Set Rotation keyframes for the hour hand. Select the Rotation property for the minute hand and choose Animation > Add Expression. Drag the pick whip to the hour hand's Rotation property. The following expression appears: thisComp.layer("hour hand").rotation To make the minute hand rotate 12 times as fast as the hour hand, add *12 at the end of the expression as follows: thisComp.layer("hour hand").rotation*12