Complex sentence: The project was conceived by Danny Hillis in 1986 and the first prototype of the clock began working on December 31,1999, just in time to display the transition to the year 2000.
Split into simpler sentences: The project was conceived by Danny Hillis in 1986. The first prototype of the clock began working on December 31,1999, just in time to display the transition to the year 2000.