(1)
  Homework : open ended; try some kind of graphics with Polygon, Line, Cuboid, etc.  Feel free to start with what I've done and alter them,
  including the turtles
  
  (2)
  Coordinate systems:  PlotRange vs ImageSize vs bounding rectangle in Raster graphics
  
  (3) more graphics examples: this file, pictures.nb file, and examples from early in semester - fractals 



So let's draw some random polygons in random colors.

randSmall := Random[Integer, {0, 20}];
randBig := Random[Integer, {0, 80}];
randColor := 
        RGBColor[Random[], Random[], Random[]];
randPoly := 
        Module[{offset}, 
offset = {randBig, 
              randBig}; 
Return[
            Polygon[ 
              Table[offset + {randSmall, randSmall}, {Random[
                    Integer, {3, 
                      6}]}]]];
];
randGraph := 
        Graphics[ 
          Table[ {randColor, 
              randPoly}, {200}]];
showRandGraph := 
        Show[randGraph, 
PlotRange -> {{0, 100}, {0, 
                100}}, 
AspectRatio -> 
            1, 
ImageSize -> {20, 20}];

Do[showRandGraph, {20}]

(* 
      How would you make an animation where they move around ,  
or where they change shape ? 

Class exercise  ...  *)

Table["i=" <> ToString[i] <> " and j=" <> ToString[j], {i, 1, 
          3}, {j, 100, 103}] // TableForm

g = randGraph;

FullForm[g]

?*Animate*