It is difficult to see well in my crude graph and chickenscratch.................the blue line.................is from (2, 0) to one unit above (-1, 0)...........................into 3d.........................just imagine it.............2d to 3d..............like 2, 3............the start of all primes..............the square root of 13 is the hyp of a right triangle with two lesser sides of 2 and 3.................