A variation of standard trap is Wobble or Wobble Trap. The main differences are much more extreme target flight path than in standard trap shooting (the trap oscillates up and down as well as side to side), shooters are allowed two shots per pull, and shooters at stations 1 and 5 stand at the 18 yard (16.5 m) mark while positions 2-4 stand at the 17 yard (15.5 m) mark. Although this version of trap is not sanctioned by the ATA many shooters consider it to be more challenging and engaging as well as more realistic preparation for bird hunting. More experienced shooters will often shoot from the Skeet positions to increase the difficulty.