You get accustomed to some unusual specifications in the concrete game, but we were admittedly stumped for a while when one of the requirements of a recent job was that the concrete surface be rough enough so that youngsters would be unable to write on it. This strange requirement turned up in connection with a tilt-up wall project, in which great stress was also laid on the need that the wall be attractive, inexpensive and easy to apply. We conducted experiments in our laboratory with the view to developing some technique which would result in a very rough concrete surface at low cost. Small casting panels were built and filled with several sizes of gravel and crushed rock, and then covered with plastic membrane to form the base material for casting concrete. Under laboratory conditions it was found that the underside of the slab could be roughened in this fashion in many attractive patterns by simply varying the base material. It is our belief that the dimpled surfaces produced by the use of a base rock course and plastic sheeting have a place in home and industrial concrete as well as in schools. We know of at least one contractor who plans to precast sidewalk and patio sections by this method. The process can also be varied to produce an attractive exposed aggregate surface. In place of the plastic sheets, this would involve using a colored stone base material covered with mortar worked well into the voids. The colors of the exposed rock can be highlighted by using a white cement-sand mortar, and some designs may include the use of redwood strips and other such devices to achieve special effects.