Amazon chief technology officer Jon McCormack has left the company for the second time, this time to work for Google.

McCormack will work for Google’s Advanced Technologies and Projects group (ATAP), which works on futuristic projects such as wearable technologies.

Earlier this year, McCormack left Amazon for Yahoo, where he worked for two months as the vice-president of engineering, before coming back to the Kindle maker.

On his return, he worked on software for Kindle, Fire phone, and project Ara along with a tiny radar system that senses hand gestures and other Amazon hardware. Most recently he reported to David Limp, who runs the entire devices business.

Re/Code cited a Google spokesperson as saying that McCormack is expected to develop ecosystem of developers to contribute to ATAP.

Led by former Pentagon research group head Regina Dugan, the ATAP team is involved in projects like augmented reality and wearable tech, with the division recently introducing a micro-sensor that can turn textiles and garments into connected devices.