Home occupation, provided that not more than 1/2 of the floor area of one story or the basement shall be devoted to such use, or, if conducted in an accessory building, the area of such use shall be limited to not more than 1/2 of the floor area of the principal structure. No merchandise or materials, either assembled or unassembled, shall be received into the residence or accessory structure for the purpose of merely storing and/or reselling. No machinery or equipment shall be used except machinery or equipment which is usually found in the home and which will not cause electrical or other interference with radio and/or television reception. No use permitted by this subsection shall result in any use operating in this zone in other than a building strictly residential in appearance. Except for permitted signs, there shall be no physical evidence of said use visible from the exterior of the building so used.