Brick-based construction toy system

1 . A brick for a brick-based construction toy, wherein the brick is of rectangular form comprised of end walls, side walls, and a top wall defining an open bottom configuration, said end and side walls having bottom edges defining a base plane parallel to said top wall, said top wall having a plurality of predictably spaced studs projecting upwardly therefrom and a plurality of similarly spaced stud-engaging elements projecting downwardly therefrom to a level near said base plane, the studs of one brick being snuggly receivable in the open bottom of a brick positioned above, with studs being frictionally gripped by elements of said end and/or side walls and said stud-engaging elements, whereby a pair of superimposed bricks are tightly secured to each other, characterized by

(a) said side and end walls being with joined with said top wall to form arcuate upper edge contours, and

(b) said side and end walls being formed with arcuate bottom edge contours between said base plane and outer surfaces of said walls such that, in an assembly of two bricks, one above the other, access grooves are formed by adjoining upper edge contours and bottom edge contours of the respective bricks to facilitate subsequent disassembly thereof.

2 . A brick according to claim 1 , wherein

(a) said side and end walls being formed with arcuate end edges where said edges are joined.

3 . A brick according to claim 2 , wherein

(a) said arcuate upper, and bottom, and end edge contours are of radii of not substantially less than about 0.005 inch.

4 . A brick according to claim 1 , wherein

(a) said arcuate upper edge contours between said side and end walls and said top wall preferentially are of a radius greater than a radius of said arcuate bottom edge contours.

5 . A brick according to claim 4 , wherein

(a) said arcuate upper edge contours preferentially are of a radius of about 0.040 inch, and

(b) said arcuate bottom edge contours preferentially are of a radius of about 0.030 inch.

6 . A brick according to claim 5 , wherein

(a) corner regions, at which said upper edge contours along side edges of said brick merge with upper edge contours along end edges of said brick, are formed with spherical contours of a radius preferentially greater than the radius of said upper edge contours.

7 . A brick according to claim 6 , wherein

(a) said spherical contours preferentially are of a radius of about 0.045 inch.

8 . A separating tool for use with an assembly of bricks according to claim 1 , which comprises

(a) a U-shaped body comprising a pair of spaced apart legs and an upper portion connecting said legs,

(b) wedge shaped elements at lower end portions of said legs,

(c) said wedge shaped elements being positioned in directly opposed relation and being insertable under pressure into an access groves formed between an assembled pair of bricks for effecting separation of said bricks.

9 . A separating tool according to claim 8 , wherein

(a) said legs are normally spaced apart a distance greater then a width of a brick and are resiliently squeezable to press said wedge shaped elements into said access grooves.

10 . A separating tool for use with an assembly of bricks according to claim 1 , which comprises

(a) a wedge shaped element, and

(b) a manually engageable element mounting said wedge shaped element enabling said wedge shaped element to be pressed into an access groove.

11 . A separating tool according to claim 10 , wherein

(a) said tool has an opposed pair of said wedge shaped elements engageable with opposed access grooves in a pair of assembled bricks.