Use of 2d6 to rep d7, d20

	2d6 make a passable "doubled die" similitude for fisting the oddball d7. By this means, the dice are rolled and summed, with any value less than or equal to 7 taken as the result, while any greater value deducts -7 for the result. This is treated as a single die roll for dice tallying purposes. It gives a d7 distribution of the 2d6's 6^2= 36 possible results as:

	1  5
	2  5
	3  5
	4  5
	5  5
	6  5
	7  6

	A d21 could then be generated by the addition of another d6 as a d3 for a 3-fold parser. An associated but simpler 2d6 technique to simulate a d20 acts by treating both d6 faces of 6 as 0, and differentiating the dice as to 1st and 2nd; applying the formula 3 *1st +2nd. It gives a d21 distribution of:

	0  1	7  2	14 2
	1  1	8  2	15 2
	2  1	9  2	16 2
	3  2	10 2	17 2
	4  2	11 2	18 1
	5  2	12 2	19 1
	6  2	13 2	20 1

	In normal usage as a d20 the 0 result would be treated as 20. Optionally, to make a more favorable high end, for results with a 1st die of 0, 3= 18, 4= 19 (& possibly 5= 20). The d10 & d% then derive from its results.