Apple spent more than two years developing its upcoming iPhone X flagship, the company’s Chief Design Officer Jony Ive said in a brief interview with Japanese design magazine Casa Brutus published Tuesday.

First spotted by AppleInsider, the interview reveals that sophisticated features like Apple’s new depth-based facial recognition system dubbed Face ID and the TrueDepth camera have made iPhone X one of the most difficult projects the company has undertaken.

iPhone X represents a new chapter in the rich history of iPhone, Ive said. The debut of the OLED device on the tenth anniversary of iPhone was a “wonderful coincidence,” he added.

Ive went on to explain that Face ID is the culmination of years of work towards a user interface that doesn’t require physical interaction, saying the system enables a heightened user experience versus Touch ID.

The designer hinted they’re already working to perfect the iPhone X’s integrated chassis and display as this will obviously become Apple’s default handset design going forward.