Types thumb|right|240px|Different types of sport climbing problems: (1) Dihedral, (2) Slab, (3) Wall, (4) Overhang, (5) Edge, (6) Roof and (7) Traverse climbing The simplest type of wall is of plywood construction, known colloquially in the climbing community as a 'woody', with a combination of either bolt-on holds or screw-on holds. Bolt-on holds are fixed to a wall with iron bolts that are inserted through the hold, which will have specific bolt points, and then fixed into pre-allocated screw-threaded holes in the wall. Screw-on holds are, by contrast, usually much smaller, owing to the nature of their fixing. These holds are connected to the wall by screws, which may be fastened anywhere on the wall's surface.
Types thumb|right|240px|Different types of sport climbing problems: (1) Dihedral, (2) Slab, (3) Wall, (4) Overhang (5) Edge, (6) Roof and (7) Traverse climbing The simplest type of wall is of plywood construction, known colloquially in the climbing community as a 'woody', with a combination of either bolt-on holds or screw-on holds. Bolt-on holds are fixed to a wall with iron bolts that are inserted through the hold, which will have specific bolt points, and then f,ixed into pre-allocated screw-threaded holes in the wall. Screw-on holds are by co,ntrast, usually much smaller, owing to the nature of their fixing. These holds are connected to the wall by screws, which may be fastened anywhere on the wall's surface.