Abstract: An invertible retaining wall block comprises a front portion, a rear portion and a neck portion connecting the front portion and rear portion. A projection extends outwardly from the block to interlock with similar blocks in adjacent courses of blocks. One or more notches are provided to the front portion in order to allow the base course of blocks to be placed in an inverted orientation with respect to subsequent courses because the notch provides clearance for the protrusion.

Abstract: An invertible retaining wall block comprises a front portion, a rear portion and a neck portion connecting the front portion and rear portion. A projection extends outwardly from the block to interlock with similar blocks in adjacent courses of blocks. One or more notches are provided to the front portion in order to allow the base course of blocks to be placed in an inverted orientation with respect to subsequent courses because the notch provides clearance for the protrusion.

Abstract: A retaining wall with a series of differently sized, pre-formed blocks. Each block includes a projection and a recess, with the projection and recess arranged and configured so that each projection effectively engages a recess in an adjacent course to connect and align adjacent courses in registry. Retaining walls made of horizontal blocks may be stacked in columnar fashion or running bond fashion. The location of the indexing surface on a projection relative to the viewable surface of the block may be varied to enable adjacent courses to be coplanar or tiered in a variety of predetermined offset distances.

Abstract: A block for use in constructing a multiple course retaining wall comprises a top surface, a bottom surface spaced apart from the top surface, opposing side surfaces, a front surface and a back surface. The bottom surface may include a pair of contacting portions that contact a top surface of a lower course of blocks when the block is placed on a lower course of blocks and a gap defining portion located between the contacting portions. The front surface may have generally planar upper and lower edges when viewed in front elevation and has a width extending between the side surfaces that is greater than the width extending between the side surfaces of back surface. At least one of the contacting portions may intersect front surface.

Abstract: A block for use in constructing a retaining wall having a bottom with a non-planar portion which creates a gap between the bottom surface and the top surface of a lower course of similar blocks when the block is placed thereon. This gap assists the block in resting on the lower course of blocks in a stable, level manner by providing a space where small amounts of rubble and dirt may exist without interfering with the stacking of the blocks. The non-planar, preferably concave, portion is also advantageous in that it reduces the unit weight of the block without significantly affecting the structural integrity of the block. Preferably, the block's bottom surface further comprises a plurality of grooves which further reduce the weight of the block and provide additional clearance in the gap for larger stones.

Abstract: The present invention relates to monoclonal antibodies of class IgG1 and IgM possessing among others the property to bind to stable heteroduplex cruciform DNA structures constructed from two DNA plasmids, to the hybrid cell lines producing such antibodies, to a method for producing the cell lines and to a method for enhancing DNA replication in a cell system containing cruciforms functioning as signals for the initiation of DNA replication.

Abstract: A device for illuminating fish tanks or the like in which a source of light positioned over the fish tank is surrounded with light absorbent material to prevent unwanted reflection or refractions and is provided with a filter which specifies the color of the illuminating light. The fish tank water is illuminated with a single color light free of unwanted refractions or reflections to muddy the color.The device includes a masking cylinder housing the light which prevents all unwanted reflections and refractions and filter cylinder movable with respect to the masking cylinder to provide a variety of color possibilities.