This alternative version of artificial white cells uses retractable tentacles, encircling the main body, to convey the idea of pathogen capture, in place of the hundreds of tiny telescoping arms that were employed in Freitas' original technical design. The artist also added intake and exhaust vents for propulsion and maneuvering. Each nanorobot is about 3 microns in size. A natural white cell is present in the background to provide visual scaling. In the lower image, the tentacles have been fully retracted.