Series of vertical recesses formed in alternate courses, as the wall is built, at a position where a future brick or block wall has to be tied (bonded) into the main wall at 90 degrees. Often used so that a junction wall may be left down, until a later date, for reason of access. Stainless or galvanised steel Integral Tie & Wall Starters are widely used to tie a new wall, at 90 deg, to an existing wall. This economic method avoids the costly task of cutting vertical indents.