Abstract: The dimensions of the blocks or bricks are, first, derived from the side lengths a, b of the tiles and, second, from the thickness d of the corner tiles, whereby an amount (a/2)-d, or (b/2)-d is obtained for the wall thickness of the blocks. The two-shell structure as well as the usual staggered arrangement by half the tile length provides a sequence of blocks of the following lengths: (a/2)-d, a/2, a-d, a, (3a/2)-d, 3a/2, 2a-d, 2a, etc. A further sequence of blocks of the following heights is obtained: (b/2)-d, b/2, b-d, b, (3b/2)-d, 3b/2, 2b-d, 2b, etc. Further sequences in respect of height and length are obtained from the two basic sequences, each smallest member being a member of a basic sequence. In a preferred embodiment, the tiles have a square visible face and the thickness a/4. Hence, the blocks have the same wall thickness and the length and heights a/4, a/2, 3a/4, a, 5a/4, 3a/2, 7a/4, 2a, etc.

Abstract: The block or brick is adapted to ensure an easy construction of a two-shell tile stove without requiring any particular skill in the art. A longitudinal center rib projects from two faces of the block adapted to contact adjacent blocks, longitudinal center grooves arranged on the two opposite faces correspond to said longitudinal rib. At least one first lateral groove whose depth and breadth corresponds to the depth and breadth of said longitudinal groove is arranged on a first side face, the marginal distances of said longitudinal groove and of said lateral groove being equal. A number of first lateral grooves whose center distance corresponds to the wall thickness of the block and second lateral grooves intersecting said first lateral grooves at a right angle are preferably provided on said first side face, said second lateral grooves being arranged and shaped like said first lateral grooves. The second side face is closed and planar, i.e. free from discontinuities.