Staircase Building Block

FIG. 1 is a front, right and top perspective view of a staircase building block, showing my new design;

FIG. 2 is a rear, left, and bottom perspective view thereof;

FIG. 3 is a front elevational view thereof;

FIG. 4 is a rear elevational view thereof;

FIG. 5 is a left elevational view thereof;

FIG. 6 is a right elevational view thereof;

FIG. 7 is a top plan view thereof; and,

FIG. 8 is a bottom plan view thereof.