Card: 'Grid Line'

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Grid Line is both a small prototype puzzle game and TCHOW's Solstice / New Year 2015 card. (And, yes, it was released about 11 months late.)

It is written in HTML5 and javascript, using a canvas element for output, and it should work in recent browsers on desktop and mobile platforms. The audio is ogg, though, so there isn't any sound on iOS.