The Viral ‘Green Glass Door’ Riddle Is a Tough One To Solve—Can You Do It?
Sliding green glass door that leads into an office area
Riddles delight and challenge the mind. Deciphering verbal puzzles or unraveling fun word games can exercise our intellect in a way other everyday tasks do not. For example, the “green glass door” riddle is an enjoyable brain teaser that has entertained kids and adults alike for years.
This riddle really shines as a group activity. Guessing together, coming up with new word pairs to test, and talking through ideas as a team is part of the enjoyment. When more people play, someone may notice a clue that others missed—that gives the group more ideas to think about. It's exciting when the pattern finally clicks and everyone understands together.
The puzzle is simple: Identify what can and cannot pass through a hypothetical green glass door based on a pattern established in a series of clues.
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What Is the 'Green Glass Door' Riddle?
The riddle goes: “There is a green glass door, and some things can go through it and some things cannot.”
The person posing the riddle then offers a series of pairs of items, only one item from each pair being able to go through the door.
For example: “A sparrow can go through but a pigeon cannot. A boot can go through but not a shoe.” The players have to figure out what allows some items to go through the green glass door and not others.
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'Green Glass Door' Riddle Examples
Here are some example pairs that help establish the pattern:
“There’s a green glass door, and a carrot can go through but a potato cannot.”
“There’s a green glass door. A rabbit or a bunny can go through but a hare cannot.”
“There’s a green glass door, and you can carry a letter through but not a postcard.”
“There’s a green glass door, and you can roll a ball through it but not a marble.”
If you believe you have figured out the pattern, go ahead and make a guess. Just be sure to frame it as a new pair of items like the original riddle, so something can come through the door and something else cannot. For instance, you could say “I think I’ve got it! Can a scooter go through the door but not a motorcycle?”
That way, even if you solved the riddle, the game can keep going for other players to keep trying to crack the code. Offering your own example pair is part of what makes it fun to solve this as a group.
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Hint To Figure Out the 'Green Glass Door' Riddle
The hint to the solution is in the name of the riddle itself. Each of the words “green glass door” has something in common with the items that are allowed through the door.
OK, spoilers ahead—read no further unless you want the riddle's answer revealed.
'Green Glass Door' Riddle Answer Reveal
The riddle's solution has to do with double letters. Look at the words "green," "glass" and "door." They all have double letters.
If a word has a double letter, it can go through the green glass door. Words with no doubles can't get in. A rabbit has double Bs, a boot has double Os. Shoes, postcards, and hares do not have any double letters, so they can’t go through the door.
'Green Glass Door' Riddle Explained
Part of what makes the riddle tricky is that our natural instinct is to compare the objects themselves—rather than the words used to describe them. When hearing pairs like “a boot can go through but a shoe cannot,” we immediately search for similarities and differences between boots and shoes to determine why one can go through the green glass door and the other cannot.
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