1)   Gravitational Lensing 1.00
With this program, one can draw images to see the effect of gravitational lensing. You can easily test the effects of several parameters by changing them and redrawing the image.
gravitational, lens, lensing, gravitation, astrophysics, einstein, bend, light, quasar, galaxy,

 2)   Pick-a-Word 1
Select longest valid words, to be replaced by the incoming letters.
pickaword, pick-a-word, cross-words, scrabble, tetris, lines, balls, marbles, Play, logical,

 3)   Cross-Numbers 1
Arrange the numbered tiles in natural order, by moving the rows and columns.
cross-numbers, xnumbers, puzzles, sam lloyd, tiles, 15, Play, logical, funny, games,

 4)   Pick-a-Line 1
Select longest lines of identical balls, to be replaced by the incoming balls.
pickaline, pick-a-line, tetris, lines, balls, marbles, Play, logical, funny, games,

 5)   Cross-Colors 1
Change the colors on a row or column, move them, and make the same color.
cross-colors, xcolors, puzzles, sam lloyd, tiles, 15, Play, logical, funny, games,