Word Switch FREE is a word puzzle for android phones and tablets which is based on the well known 15 puzzle, but instead of numbers, features letters. The objective of the puzzle is to make words from scattered letters by making sliding moves that use the empty space. You can change the size of the puzzle in range from 3 to 4, change the word puzzle difficulty level and play with one or two empty spaces. All combinations of the puzzle have a solution.
Google play: https://play.google.com/store/apps/details?id=com.leonapp.wordswitchfree