Abstract: A set of building blocks are provided for building up to a unique structure using substantially simply designed blocks. The building blocks according to the present invention are classified into a first piece P1 and a second piece P2. The first piece P1 has a groove G provided therein of which two surfaces Ga, Ga are tilted symmetrically from the reference plane H orthogonal to a flat plane S or a plane S? including the flat plane S. The bottom Gb of the groove G extends parallel with the flat plane S. The second piece P2 has at least a corner edge thereof arranged at a right angle, when viewed in the lengthwise direction of the groove G, to engage with the groove G with its one side Af coming substantially in face contact with the grooves G. In particular, the width WS of the flat plane S is greater than the width WG of the groove G along the direction perpendicular to the reference plane H while the flat plane S and the groove G are coincided with each other at the center of the width WS, WG.

Abstract: A set of building blocks are provided for building up to a unique structure using substantially simply designed blocks. The building blocks according to the present invention are classified into a first piece P1 and a second piece P2. The first piece P1 has a groove G provided therein of which two surfaces Ga, Ga are tilted symmetrically from the reference plane H orthogonal to a flat plane S or a plane S? including the flat plane S. The bottom Gb of the groove G extends parallel with the flat plane S. The second piece P2 has at least a corner edge thereof arranged at a right angle, when viewed in the lengthwise direction of the groove G, to engage with the groove G with its one side Af coming substantially in face contact with the grooves G. In particular, the width WS of the flat plane S is greater than the width WG of the groove G along the direction perpendicular to the reference plane H while the flat plane S and the groove G are coincided with each other at the center of the width WS, WG.