What is the key to the success of magician's handstand walking?

The key to the success of this magic trick lies in those boots. It turns out that the soles of these boots are equipped with pneumatic devices, and each pneumatic device generates enough suction to support twice the weight of the performer. Therefore, when the magician walks on the ceiling, even if only one foot touches the board, it is enough to attract her firmly to it. Of course, there is also a fastening device in the boot, which can tie the performer's feet firmly in the boot. In an emergency, there is a safety net under the ceiling.