Paper.js renderings of #118, #328, and #391

A friend recently introduced me to the work of Sol Lewitt, and I became instantly intrigued by it. It became pretty obvious that a lot his instructions would be fun and interesting to recreate in code, so I was very happy to come across Solving Sol.  

I've done these three (#118, #328, and #391).  Please give me any feedback you have on the code, and thanks for considering my pull.

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Wall Drawing #118 (1971)
On a wall surface, any continuous stretch of wall, using a hard pencil, place fifty points at random. The points should be evenly distributed over the area of the wall. All of the points should be connected by straight lines.

![image](https://cloud.githubusercontent.com/assets/2388782/3697283/2add3986-13a3-11e4-9d96-bb8485b419a7.png)

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Wall Drawing #328 (1980)
On a black wall, a white circle within which are white vertical parallel lines, and a white parallelogram within which are white horizontal parallel lines. The vertical lines within the circle do not enter the parallelogram, and the horizontal lines within the parallelogram do not enter the circle.

![image](https://cloud.githubusercontent.com/assets/2388782/3697285/3e3b8384-13a3-11e4-9fd1-3385dbf4d943.png)

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Wall Drawing #391 (1983)
Two-part drawing. The two walls are each divided horizontally and vertically into four equal parts. First wall: 12-inch (30 cm) bands of lines in four directions, one direction in each part, drawn in black India ink. Second wall: Same, but with four colors drawn in India ink and color ink washes.

![image](https://cloud.githubusercontent.com/assets/2388782/3697351/1c2ca79e-13a5-11e4-90a4-5463da7f5cd9.png)