Adjoin — Complete Game Guide

How to Play

Each puzzle shows a grid with several pairs of colored dots. To solve the puzzle, you must draw a path connecting each pair of same-colored dots. The challenge: your paths must fill every single cell in the grid. You cannot leave empty cells. You cannot cross another color's path.

• Tap or click a dot to start a path
• Drag from one dot to trace the path across the grid
• Release and touch again to resume from where you left off
• To backtrack, drag back over your own path to erase it from that point

The Fundamental Rule: Fill Every Cell

This rule is what makes Adjoin a puzzle rather than just a coloring exercise. If you connect all pairs but leave cells empty, the puzzle is not solved. This constraint is actually your most powerful deduction tool — if a cell can only be reached by one color without blocking everything else, you know exactly which color must go there. Always keep 'can every remaining cell still be reached?' in mind.

Solving Strategy: Work the Edges First

Corners and edge cells are heavily constrained — they can only be approached from one or two directions. Start by tracing paths that are forced to go along edges. Edge analysis often determines 60 to 70 percent of the solution in harder puzzles before you even touch the interior.

• Corner cells can only be approached from two directions maximum
• Edge cells that lie between two same-colored paths have forced routing
• Identify which paths must pass through corners and solve those first

Solving Strategy: Count the Cells

Before you start drawing, count the total cells in the grid and the number of colors. Every cell must belong to exactly one path. If a region of the grid is isolated from all but one color's reachable area, that color must fill that region entirely. Cell counting helps you detect forced solutions in enclosed areas.

Solving Strategy: Avoid Dead Ends

A dead end happens when your path paints itself into a corner — surrounded by already-drawn cells with nowhere to go. To avoid dead ends:

• Draw paths away from areas that are already getting crowded
• If you notice a corner region forming, make sure the right color is routing into it
• Ask: 'If I draw this path this way, can all remaining empty cells still be reached?' If no, backtrack

Using the Displacement (Draw-Through) Feature

Adjoin includes a displacement mechanic: if you drag your current color into the middle of another color's path (not its endpoint dot), the other color's path is erased from that intersection onwards and yours continues through. This is useful when you realize a path needs to be rerouted but another color is in the way. You can re-route the displaced color afterward.

Difficulty Progression

The 12 built-in levels scale from small grids with two colors to large grids with six colors:

• Levels 1–2: 4×4 grid, 2 colors — learn the mechanics with simple routing
• Levels 3–4: 5×5 grid — more cells, more constraint to analyze
• Levels 5–7: 6×6 grid with 4–5 colors — cell counting becomes critical
• Levels 8–10: 7×7 grid — edge-first and dead-end-avoidance strategies essential
• Levels 11–12: 8×8 grid with 6 colors — full strategic toolkit required

Quick Tips

• Work corners and edges first — they are the most constrained
• If a path seems wrong but leads nowhere else, it is probably forced
• Remember you must fill every cell, not just connect the dots
• When stuck, ask which color could possibly reach an isolated cell

Bottom Line

Adjoin puzzles are satisfying precisely because every solution is derivable through pure logic. There is no luck involved — every puzzle is designed to be solvable without guessing. The more levels you complete, the better you become at spotting forced moves, which makes even hard puzzles feel approachable with patience and systematic thinking.

Frequently Asked Questions