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# A6: Due 11/23 at 11:30am

The goal of this homework is to implement the specifications in Fig. 3 A-D of the edge detection paper: http://www.taborlab.rice.edu/pdf/tabor_cell_2009.pdf.

- First, come up with a way to make a mask with a non-diffusing, non-reacting signal. Make a few different masks: a circle, a square, a star.

- Next, come up with a way to lay out a bed of E coli cells in a semi random grid spaced one body length apart and with random orientations (use ecoli ( [ x := 10, y := 11, theta := 1.57 ], program p() ) ). The growth rates of the cells should be set to zero.

- Implement each of the specifications in Fig. 3 on each of your patterns Use GFP as the output. Show how changing the diffusion rate and degradation rate of AHL affect the quality of the result. For this part, you can just use one mask and only the final edge detector circuit.

- Make figures like in the middle column of Fig. 4 or in Fig. 5 A. Do this by analyzing a screen shot of your pattern in something like imageJ.