Low Level or Slant Top slot machines include a stool so the player has sitdown access. 46 Mike Dixon, PhD, professor of psychology at the University of Waterloo, Ontario, Canada, 47 studies the relationship between slot players and slot machines.A person playing a slot machine can insert cash, or in ticket-in, ticket-out machines, a paper ticket with a barcode, into a designated slot on the machine. (citing to Ferguson. The Slot Machine Answer Book: How They Work, How They've Changed, and How to Overcome the House Advantage (Bonus Books, 2005) isbn Legato, Frank. Several states ( Illinois, Indiana, Louisiana and Missouri ) allow slot machines (as well as any casino-style gambling) only on licensed riverboats or permanently anchored barges. American Indians: Answers to Today's Questions, 2nd edition, University of Oklahoma Press, 2001 (362) Indian Gaming Regulatory Act. The scatter symbol is usually a special symbol, which means the wild symbol cannot replace it, although in some games the wild symbol also substitutes for scatters.