WEST LAFAYETTE, Ind. (AP) — A team of Purdue University students concocted a 156-step recipe to prepare a hamburger to win Saturday's annual national Rube Goldberg Machine Contest.

This year's task was to assemble a burger consisting of no less than one precooked meat patty, two vegetables and two condiments, sandwiched between two bun halves.

The victory by the 17-member Purdue Society of Professional Engineers was the team's third such win in the past four years in the contest, named for the late cartoonist known for his drawings of complicated devices performing simple tasks.

Texas A&M University placed second; the University at Buffalo in New York was third.

After winning the regional contest in February, Purdue's team added 55 more steps to perfect its machine, said captain Drew Wischer.

"We put 4,000 to 5,000 man-hours into this machine since September, and all the hard work has been well worth it," said Wischer, a senior in aviation technology from Cedarburg, Wis.

The competition, sponsored by Phi Chapter of Theta Tau fraternity, rewards machines that most effectively combine creativity with inefficiency and complexity. Machines must complete the assigned task in 20 or more steps.