Sixteen tiles. Hidden among them are four four-letter words that use every tile exactly. Tap tiles and they go straight onto the highlighted row; tap Place word to put the word down.

• Plenty of words can be made. Only some sets of four use up all sixteen tiles, so three good words can still leave you holding nonsense.
• The highest empty row is highlighted. Tap any other empty row to put your word there instead.
• Tap a word already on the grid to take it back. The others stay where they are.
• With all sixteen down, drag a word up or down to try another order. The same words on different rows catch different squares and make different columns; the score follows. Tap Finish when you're happy.
• Columns that happen to read as a word score a bonus too, top to bottom. A full four-letter column scores double. Columns read from the top row, so they count once every row above them is filled.
• Finish inside five quiet minutes and you keep a point for every five seconds left, up to 60. There is no clock on screen.
• Properly stuck? I'm stuck finds you a word that still leaves a way home. Once per game, and it costs 20 points.
• Had enough? Give up ends the day where it stands: what is on the grid scores, the clock pays nothing, and GuffBot will show you the best line.
• Drag the tiles in your hand to rearrange them. A quick tap still picks one.
• On a keyboard you can simply type the word. Backspace takes a letter back, enter places it, escape clears, and the up and down arrows move between empty rows.

A premium square counts on the turn you cover it, and it counts for the column too. Later words score their own squares, not yours.