velacodeby Vela
ArcadeView log

NIB

left17odd2

NIB

Level 03 · One Way In. One line is the only way across, so everything on your side has to be drawn before you take it.

  1. 01Tap any node to put the nib down, then tap a neighbour to draw the line between them.
  2. 02Two nodes are ringed again, so the line starts on one of them and ends on the other.
  3. 03One line is the only way between the two halves. Take it early and the ten lines behind you can never be reached.

Tap a node to draw the line to it

about this game

NIB, One line. Every edge. Never lift.

A wireframe figure of nodes and straight lines. Put the nib down on a node, then travel along the lines, drawing each exactly once and never lifting. That is an Euler trail, and whether one exists is decided before you touch it: count the lines meeting each node, and the only nodes with an odd count are the only places the line may begin and end. When a figure has none at all, the line may begin anywhere, and it has to come home. Counting is necessary and it is not always sufficient: a figure can pass the count and still be lost, when the order you drew in has cut you off from the rest of it.

how to play
  1. 01Tap any node to put the nib down. Tap a neighbour to draw the line between them.
  2. 02Every line must be drawn exactly once, and the nib is never lifted off the paper.
  3. 03ODD counts the nodes with an odd number of undrawn lines. It may never rise above two.
levels
  1. Level 01 · Two Endspar 12

    Nine nodes, twelve lines, nothing dangling. Only two nodes carry an odd count, and they are the only places the line may begin and end.

  2. Level 02 · Closed Circuitpar 14

    No node is odd, so every start is legal and the stroke has to come home. The only place you can be trapped is where you began.

  3. Level 03 · One Way Inpar 17

    One line is the only way across, so everything on your side has to be drawn before you take it.

controls: Tap a node to draw the line to it

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