I created the PowerPoint presentation below from two quick painting demos I recently did for my class on the Bayou St. John – one was done on an overcast day and one was done on a partly cloudy day with the sun out. I made two other transitional images in Photoshop by modifying images of the paintings and then created timed dissolves between the images in PowerPoint. The purpose of this presentation is to illustrate the temporal nature of our visual sensation and perception of a scene where the sun is going in and out from behind the clouds. You may need Microsoft PowerPoint to run it. I believe there is freeware to play PowerPoint presentations only without the capability to create or edit them.