Human land use change, specifically development of land, can indirectly affect riffles and riffle quality. Riffle shuffles may be used to define the shuffle algebra. The hornyhead chub inhabits riffle/pool sections of small streams to medium-sized rivers. Spawning sites are usually a bed of fine gravel in a riffle above a pool. The interlacing is given by the riffle shuffle permutation. By Riffle Stacking the cheat stacks the card(s) while doing a Riffle shuffle. This method involves placing gravel on a riffle board with a bellows placed underneath it. For an formula 3-card deck, the number of riffle shuffles needed grows as formula 4. Riffle and pool habitats are favorable for many cold water fish species. There are some games, however, for which even seven riffle shuffles are insufficient. Grouvellinus leonardodicaprioi is a species of riffle beetle in the superfamily Byrrhoidea. Stonecats occupy gently to fast-moving riffle areas with rocky substrates. There are many different versions of the riffle splitter. Riffle boxes are commonly used in mining. The riffle test is less effective for detecting cards marked with luminous and juice methods.