FIG. 1 is a top plan view of a 1st embodiment;
FIG. 2 is a bottom plan view thereof;
FIG. 3 is a side elevation view thereof;
FIG. 4 is an elevated perspective view thereof;
FIG. 5 is a top plan view of a 2nd embodiment showing a dual block;
FIG. 6 is a bottom plan view thereof:
FIG. 7 is a side elevation view thereof;
FIG. 8 is an end elevation view thereof;
FIG. 9 is an elevated perspective view thereof;
FIG. 10 is a top plan view of a 3rd embodiment showing a quad block;
FIG. 11 is a bottom plan view thereof;
FIG. 12 is a side elevation view thereof;
FIG. 13 is an end elevation view thereof;
FIG. 14 is an elevated perspective view thereof;
FIG. 15 is a top plan view of a 4th embodiment showing a an elongated block;
FIG. 16 is a bottom plan view thereof;
FIG. 17 is a side elevation view thereof;
FIG. 18 is an elevated perspective view thereof;
FIG. 19 is a top plan view of a 5th embodiment showing a dual elongated block;
FIG. 20 is a bottom plan view thereof;
FIG. 21 is a side elevation view thereof;
FIG. 22 is an end elevation view thereof;
FIG. 23 is an elevated perspective view thereof;
FIG. 24 is a side elevation view of a 6th embodiment;
FIG. 25 is a top plan view there of;
FIG. 26 is bottom plan view thereof;
FIG. 27 is an end elevation view thereof;
FIG. 28 is an elevated perspective view thereof;
FIG. 29 is a top plan view of a 7th embodiment without contrasting shading;
FIG. 30 is a bottom plan view thereof;
FIG. 31 is an elevated perspective view thereof;
FIG. 32 is a side elevation view thereof;
FIG. 33 is a top plan view of an 8th embodiment showing a dual block without contrasting shading;
FIG. 34 is a bottom plan view thereof;
FIG. 35 is a side elevation view thereof;
FIG. 36 is an end elevation view thereof;
FIG. 37 is an elevated perspective view thereof;
FIG. 38 is a top plan view there of a 9th embodiment showing a quad block without contrasting shading;
FIG. 39 is a bottom plan view thereof;
FIG. 40 is a side elevation view thereof;
FIG. 41 is an end elevation view thereof;
FIG. 42 is an elevated perspective view thereof;
FIG. 43 is a top plan view of a 10th embodiment showing an elongated block without contrasting shading;
FIG. 44 is a bottom plan view thereof;
FIG. 45 is a side elevation view thereof;
FIG. 46 is an elevated perspective view thereof;
FIG. 47 is a top plan view of an 11th embodiment showing a dual elongated block without contrasting shading;
FIG. 48 is a bottom plan view thereof;
FIG. 49 is a side elevation view thereof;
FIG. 50 is an end elevation view thereof;
FIG. 51 is an elevated perspective view thereof;
FIG. 52 is a top plan view of a 12th embodiment without contrasting shading;
FIG. 53 is a bottom plan view thereof;
FIG. 54 is a side elevation view thereof;
FIG. 55 is an end elevation view thereof; and,
FIG. 56 is an elevated perspective view thereof.
The blocks in FIGS. 1-28 are shaded with diagonal lines to show a contrast in appearance relative to portions with no diagonal lines.