# dinkolas-Scope

Design PDF: dinkolas-praxinoscope-output ##### About

I wanted to create a caterpillar-like creature for my praxinoscope. Most of the motion was simple enough, just sines and cosines with offset phases took care of it. However, it took some tricks that I'm pretty happy with to implement knees and a ground. The location of the knees is found by intersecting two circles, one centered at the hip and the other centered at the foot (thanks to johannesvalks on Stack Exchange for the equations for circle intersection). In order for there to be a ground, the feet move in a circle except the y coordinate is clipped to a minimum value. The code is pretty rough, but it works!

##### Code

I used Golan's Java Processing template. Here's my code in drawArtFrame():

```void drawArtFrame (int whichFrame) { // Draw the artwork for a generic frame of the Praxinoscope, // given the framenumber (whichFrame) out of nFrames. // NOTE #1: The "origin" for the frame is in the center of the wedge. // NOTE #2: Remember that everything will appear upside-down!   //Intersection of two circles from johannesvalks on Stack Exchange stroke(128); strokeWeight(1); line(50,-29,-50,-29); stroke(0); strokeWeight(2); fill(0); float t = map(whichFrame, 0, nFrames, 0, 1); float segments = 6; for (float i = 0; i &lt; segments; i++) { float x1 = map(i,0,segments-1,-35,35); x1 += map(-sin(t*TWO_PI-i+.75),-1,1,-1,1); float y1 = map(cos(t*TWO_PI-i),-1,1,-10,0); ellipse(x1,y1,15,15); float x2 = map(-cos(t*TWO_PI-i),-1,1,x1+5,x1-5); float y2 = map(sin(t*TWO_PI-i),-1,1,-30,-20); y1 -= 15/2; y2 = max(y2,-27); float mult = sqrt(2*20/(pow((x1-x2),2)+pow((y1-y2),2))); float kneexLoc = ((x1+x2)+mult*(y2-y1))/2; float kneeyLoc = ((y1+y2)+mult*(x1-x2))/2; line(x1,y1,kneexLoc,kneeyLoc); line(kneexLoc,kneeyLoc,x2,y2); rect(x2-4,y2,4,1);   x2 = map(-cos(t*TWO_PI-i+2.5),-1,1,x1+5,x1-5); y2 = map(sin(t*TWO_PI-i+2.5),-1,1,-30,-20); y2 = max(y2,-27); kneexLoc = ((x1+x2)+mult*(y2-y1))/2; kneeyLoc = ((y1+y2)+mult*(x1-x2))/2; line(x1,y1,kneexLoc,kneeyLoc); line(kneexLoc,kneeyLoc,x2,y2); rect(x2-4,y2,4,1); }   }```