Sea Crates

Block It Out (also known as Sea Crates) is a recurring challenge in Survivor.

Rules
A pair of castaways from each tribe would swim out into the ocean to retrieve one of four crates with a different color on each face of a crate. Between the beach and crates would be a "battle zone" marked off by four flags. Within this zone, an opposing tribe member would try to prevent the two castaways from crossing the zone and reaching the crate. Once the two castaways crossed the zone, they would bring a crate back to the beach, and a second pair of castaways would go out to retrieve another crate. Once all four crates were retrieved, the crates would need to be stacked so that one color didn't show more than once on each column. The first tribe to complete the puzzle would win.

In, this challenge was modified for individual use. Instead of having to retrieve the crates from the sea, the castaways would solve a puzzle to obtain a hatchet and cut a rope which would drop a bag with the colored cubes.

In, the castaways would bounce the blocks along a rope tunnel to retrieve them.

History
In, Galu never lost their lead and won their third consecutive immunity and comfort items, sending Foa Foa to Tribal Council.

In, the challenge was used as a Redemption Island Duel. Even though Edna Ma received verbal assistance from the other castaways, Ozzy Lusth was able to continue his winning streak, eliminating Edna from the game.

The challenge re-appeared in as a Redemption Island duel yet again. After finishing first, Laura Morett helped Tina Wesson, who was in last place, complete her puzzle, and defeat Vytas Baskauskas, eliminating Vytas from the game.

The challenge appeared as a post-merge reward challenge in, where the castaways had to paddle boats to retrieve four colored crates. The magenta team had trouble paddling their boat, giving the green team a headstart on their puzzle. Ultimately, the green team won.

Trivia

 * Laura Morett is the only person to compete in this challenge twice.
 * Both times she competed, she won.
 * This challenge has been used in increments of four seasons, starting with season 19 in, followed by season 23, , then season 27, and lastly season 31,.