groove is part of:

groove contains:

Full expansion for groove:
   100%  1.5x2 Plate w/ Horiz. Side Groove
   100%  1.5x8 Plate w/ Horiz. Side Groove
   100%  1x2 Brick w/ Vert. Side Groove
   100%  1x4 Horizontal-Grooved Brick
   100%  2x2x6 Brick w/ Vert. Side Groove
    60%  2.5x14 13-Rung Extension-Ladder Piece
    30%  4x4x1.3 Grooved Hub w/ 7 Peg Holes
    30%  4x4x1.6 Grooved Hub w/ 7 Peg Holes