In some implementations, the mounting plate 800 includes a first open slot 802 and a second open slot 804 that are perpendicular to each other. For example, the first open slot 802 may be aligned with and parallel to a longitudinal edge of the elongated mounting plate 800, and the second open slot 804 may be oriented to be perpendicular with the longitudinal edge. Each of the first and second open slots 802 and 804 is configured to receive a body of a fastener e. g. , a screw and block an enlarged head of the fastener. Each of the first and second open slots has a respective width that is larger than a first width of the body of the fastener and smaller than a second width of the enlarged head of the fastener.