Fixed bounds error in Lua version and x-step sign
Fixed bounds error in Lua version and x-step sign

UCL-RITS/pi_examples,UCL-RITS/pi_examples,UCL-RITS/pi_examples,UCL-RITS/pi_examples,UCL-RITS/pi_examples,UCL-RITS/pi_examples,UCL-RITS/pi_examples,UCL-RITS/pi_examples,UCL-RITS/pi_examples,UCL-RITS/pi_examples,UCL-RITS/pi_examples,UCL-RITS/pi_examples,UCL-RITS/pi_examples,UCL-RITS/pi_examples,UCL-RITS/pi_examples,UCL-RITS/pi_examples,UCL-RITS/pi_examples