leemsa This model is made with Geogebra by Jason Sham.permalink

leemsa Thanks for the suggestion, as shown in http://screenr.com/Liqs But note that in my demo, the octagon is not regular.permalink

mathteacher1729 This is possible in geogebra (v 3, anyway). Create a slider (angle) between 0 and 360 named alpha. Then create a polygon with 8 sides. Then find the center by the intersection of the top left and bottom right points in any two parallel sides. Rotate that center point about the angle alpha. :) permalink

mathteacher1729 This is fantastic, thank you for sharing! permalink

leemsa The applet is here: http://dl.dropbox.com/u/4210789/dg/slope110917a.htmlpermalink

leemsa See how the cos wave seems to move to the left. If you focus on each dot, they are simply moving up and down. Each dot is repeating movement of another on its right, but remaining on the same horizontal position. That's how the over all pattern seems to move in the opposite direction.permalink

leemsa The geogebra applet is here: http://dl.dropbox.com/u/4210789/dg/cos_shift.htmlpermalink

leemsa Here are the applets for playing with these patterns: http://dl.dropbox.com/u/4210789/dg/circle_pattern.html http://dl.dropbox.com/u/4210789/dg/poly_pattern.html http://dl.dropbox.com/u/4210789/dg/img_pattern.htmlpermalink

leemsa RT @leemsa quadratic graph with 3 points http://dl.dropbox.com/u/4210789/dg/ggb_sgrid.htmlpermalink

leemsa RT @leemsa study relation between perimeter and area of randomly generated rectangles permalink