Strands

Pick each base so the strand folds back on itself into exactly the right shape.

How to play

Set the bases along an RNA strand so it folds into the target shape. Pairing follows the rules A with U and G with C, so the bases you choose decide which parts of the strand bond and how it folds.

• Set each position to A, U, G or C
• Remember A pairs U and G pairs C when the strand folds
• Match the target fold shape to solve the puzzle
• Harder levels use longer strands and trickier folds

Game modes

• Easy, Medium or Hard difficulty
• Daily puzzle or Practice for fresh strands

Controls

• Desktop: click a base to cycle A to U to G to C, or use arrow keys to move and A/U/G/C to set
• Phone & tablet: tap a base to cycle it through the four options

Tips & strategy

• Work out which positions must pair in the target fold, then make those bases complementary
• Place the stems (paired regions) first; loops are the leftover bases
• If the fold is wrong, check for a mismatched pair before changing everything

What you'll learn

Strands is a molecular-biology puzzle about RNA base pairing and folding, building intuition for how nucleic acids form their shapes.

• Skills: molecular biology, RNA, base pairing, nucleic acid structure
• Best for: roughly grades 9–12 (ages 14+)
• For parents & teachers: hands-on practice with base-pairing rules.

About Strands

Strands is a molecular-biology puzzle about RNA base pairing and folding. It's an original, free browser game built in-house for PlayPendium.

A free, original browser game on PlayPendium — no download, no install. Browse all games →