Hello; I did some searching last fall for a neighbor for binding straps. Places, Northern Tool & Hydraulics for example, had narrow nylon binding straps in rolls of long lengths with tools to pull them tight. ( You may have purchased items in large boxes with these type straps around the box.)They were intended to be bindings for large packages. There were more sturdy metal clips and also nylon type to fasten the binding straps. Perhaps a band of thes straps around the outside of each row of block would hold the block in place and be easy to remove later?? There are also plastic corners that can be placed under the straps at the corners of the blocks to prevent the straps from braking at those stress points.