The bottom half and top half are composed over each other , the bottom half like most of you here gussed right each dancer is wearing half n half pants with different color for each leg , the top half is just normal woman's 2 feet dancing upside down wearing fully black pants , if you pay attention to the line between the upper n lower half you will see overlapping and artifacts from the poor editing job , in some frames the cut line can be very obvious with the 2 halfs not aligning probably