Twice a year, during freeze-up and break-up, jumbled ice stops travel across the river that divides the old and new villages of Kasigluk.

Sometimes it's too dangerous to cross for three days, said Carl Williams, principal of one of two schools in the Western Alaska community. Other times people are stranded for three weeks.

Those on one side of Kasigluk can't get to the store, while health aides, unable to reach the clinic, are forced to work out of the school, said a group of village middle school students who outlined the problem at an annual robotics and engineering competition Saturday in Anchorage.

The kids have a solution, they say: Build a bridge, build boardwalks and pay for everything with federal development grants.

"It should be strong so sno-gos and four-wheelers can go on it; it should be tall so boats, sno-gos and cars could go under," the students said in a video they created for the competition.

The idea was one of more than 120 solutions put forth Saturday to transportation problems across Alaska, each pitched by teams of students 9 to 14 years old at Dimond High School for the Anchorage Robot Rendezvous.

Teams in matching T-shirts with names like the "Robo Freakos" and "Internet Exploders" brought football-sized robots built with LEGOs -- each programmed to earn points by rolling and waddling its way across a plywood playing field. Other categories in the contest rated students on their ability to solve problems, like the ice blockade between old and new Kasigluk.

The lessons learned here could begin a path toward future careers as engineers, said Vicki Nechodomu, a Kasigluk teacher and coach for the community's robotics team.

Her students presented their bridge idea to elders at the village traditional council in November. The council asked the kids to come back this month to talk some more.

"They got to try their hand at having power in the community," Nechodomu said.

For Bush students the annual contest also means a rare trip to Anchorage.

"They went shop-o-mania," said 13-year-old Isaiah Andrews, nodding to the Kasigluk girls. The group hit Dimond Center on Friday night, stopping in Lids and Journeys and Old Navy, they said.

Some of the students speak English as a second language. One boy on sensory overload bumped into a glass partition that he mistook for an open entryway to the mall, said Newtok principal Grant Kashatok.

"Smooshed his nose on there."

Erin Anvil, a Kasigluk 13-year-old who programmed the team robot to rack up points by flinging plastic hoops, said this is her first trip to the city. She ordered two ice cream cones at Golden Corral the night before.

The team traveled from Bethel with the Newtok Yungaqs, four teenagers who earned a spot at the state competition along with Kasigluk at a regional robotics competition. Both the Lower Yukon Kuskokwim School District squads come from towns facing daunting civic and engineering challenges.

Kasigluk has its semi-frozen river while Newtok leaders are trying to move their entire community to escape erosion.

There are no roads in the village, only boardwalks. Asked by contest organizers to tackle a transportation problem in their home town, the Newtok students created an Eskimo dance to show why kids should wear helmets when biking on the bumpy walkways.

Back in the Dimond gymnasium, the smell of popcorn and the plastic tarps covering the floor filled bleachers. Parents crowded the sidelines for the main event: A three-round robotics showdown where teams score points by unleashing their pre-programmed robots on a kind of LEGO obstacle course.

No rock-em, sock-em robots here. The point of the competition is to complete "missions" like carrying LEGO passengers to a drop zone without knocking stuff over. An iPod-size computer, programmed by the kids on laptops, drives the robot.

Kasigluk scored 155 points in the first round -- a personal best for the team but not enough to win. At the beginning of round two, the team crowded around the waist-high playing field and launched the machine.

A pencil-size arm scooped up a plastic hoop, drawing cheers, but soon the robot toppled, its tracks whirring in the air.

The squad had about an hour to tweak their robot's programming for the next round. Nechodomu, the coach, called a huddle.

You guys want to try to do better, she asked.

"Yeah!"

"All right," she said. "What are we going to change?"

In the final round the team beat their best score by 100 points.