//Include AccelStepper library:
#include <AccelStepper.h>

// Create a new instance of the AccelStepper class:
AccelStepper X_LR = AccelStepper(motorInterfaceType, X_LR_stepPin, X_LR_dirPin);
AccelStepper X_LL = AccelStepper(motorInterfaceType, X_LL_stepPin, X_LL_dirPin);
AccelStepper X_TR = AccelStepper(motorInterfaceType, X_TR_stepPin, X_TR_dirPin);
AccelStepper X_TL = AccelStepper(motorInterfaceType, X_TL_stepPin, X_TL_dirPin);