Terasu: Light Up

Terasu is a light-and-logic puzzle: place bulbs on an empty grid until
every cell glows. Each bulb lights its entire row and column until a wall
blocks the beam and no two bulbs may ever see each other. Numbered walls
tell you exactly how many bulbs must touch them. One clean rule set,
infinite boards, nothing to read, nothing to memorize.

HOW TO PLAY
• Tap a cell to place a bulb, tap again to clear it.
• Switch to Mark mode to cross off cells you know are empty.
• A wall's number turns green the moment it's satisfied — red if you've
placed too many bulbs around it.
• No timer pressure, no lives, no fail state. Mistakes just pulse red so
you can fix them and keep going.

FOUR DIFFICULTIES
Easy, Medium, Hard, and Expert: each one graded by the hardest logical
deduction it demands, not just by grid size. Expert unlocks once you've
proven yourself on Hard.

DAILY PUZZLE
One shared board every day, the same for every player. Build a streak by
coming back. Miss a day and it resets, so the calendar keeps you honest.

TRACK YOUR PROGRESS
Best time and rolling average, tracked separately for every difficulty.
Every solve is a chance to beat your own record.

PLAY YOUR WAY
Endless mode for whenever you have a spare minute, daily mode for a
once-a-day ritual. Stuck? A hint is one tap away.