A flammable gas concentration detection apparatus including an energization control unit that switches the energization state of heating resistor at regular time periods TW, and a gas concentration computation unit. The housing defines two recesses in respective opposite side portions of a bottom thereof, and two symmetric grooves in opposite sides of a rear surface thereof. The poker table layout may include two chip areas at each player station to accommodate different sets of chips\u2014one for each poker game being played simultaneously. If not, the product itself is designated a prime motivator product and a prime motivator count associated with the product is incremented.