curvilinear shapes frequently are more desirable due to the ease of removal of the block from a mold fig9 and 10 illustrate another embodiment of the block block 200 is similar to blocks 100 and 100 a of fig3 to 8 except that there are no chamfers on the front of the block the absence of chamfered edges and corners is that the top and the bottom of the block are interchangeable that is if block 200 is flipped over it is a mirror image of another block 200 by contrast the mirror image of block 100 would have to be manufactured separately if it is desired to use the block in more than one orientation when constructing a retaining wall fig9 and 10 show block 200 having parallel top face 202 and bottom face 203 the length of face 204 is defined by the distance between corners 206 and 207 extending from front portion 210 are two legs 220 and 230 cores 221 and 231 are located primarily in the legs though they extend into front portion 210 legs 220 and 230 extend to rear portions 224 and 234 respectively having rear faces 225 and 235 respectively front face 204 and rear faces 225 and 235 each extend from top face 202 to bottom face 203 the distance between faces 202 and 203 defines the thickness of the block legs 220 and 230 are separated by void 240 each leg 220 and 230 has two side walls 222 223 and 232 233 respectively generally converging from the front to the back of the block block side walls 211 and 213 extend from top face 202 to bottom face 203 pin holes 215 and 216 and pin receiving cavities 217 and 218 are located on the front portion of.