Excel file: 11. Cardioids
Challenge questions: 11.Challenge Questions
Challenge questions if you have also done File 6: 11.Cardioid Counting Questions
A cardioid can be obtained by connecting vertices of the polygon (1, 2), (2, 4), (3, 6) … (j, 2*j) for j = 1, …, n-1. Of course, many of the 2j second vertices will be larger than n in size … these points are simply the MOD n values of 2*j (MOD is the remainder upon division by n). For example, if n = 6 and j = 4 then the rule is to connect point 4 to 8, but 8 is the same as 2 because 2 = MOD(8, 6). Note that this is a second time to have drawn that particular line since (2, 4) was already drawn. Similarly, (5, 10) becomes (5, 4) because 4 = MOD(10, 6).
We can generalize the doubling rule to obtain multiple cardioids around the circle by changing the rule from (j, 2j) to (j, k*j). This will produce k-1 gathering points.
The cardioid images are created much like File 9, which creates general similar triangles using parallel lines, in that each of the lines is set independently from others, rather than as a single closed circuit as was the case in PART I. Interestingly, some of the relations between n and k produce images which are amenable to analysis using the counting rules discussed in PART II.
There is no paper written at this point for this file.