A new kind of puzzle

For you puzzle fans, here’s something fresh: a 3-D building puzzle from MathsNet Interactive Geometry. It’s not too clear from the interface, so here are some instructions:

• The goal is to create the 3 illustrated 2-D patterns created when looking at a 4x4x4 pattern of cubes from above, the front, and to the right. You only need one cube in the marked row/rank/column to create the pattern in profile, but the puzzle may demand more.
• The top view is looking down on the grey grid, with the arrow at the bottom pointing upwards. The “front” view is looking along the arrow. For the “right” view, rotate the grid 90 degrees to the left from the front view, so the arrow points to the right of the screen.
• To add cubes to the grid, select “build” and click the grey grid or the face of an adjoining cube. To remove cubes from the grid, select “break down” and click a cube to remove.
• There are 10 puzzles in all — select a puzzle by clicking “figuur1”, “figuur2” etc. They are not in order of difficulty; in fact #1 is one of the hardest. I suggest starting with #5 or #6 until you get the hang of it.
• You have to use exactly the specified number of cubes: no more, no less. When you make the right profile pattern in all 3 dimensions but with too many cubes, a green dot will appear next to the puzzle name — you’re close, but not there yet. You need to remove more cubes while preserving the profile patterns until the dot turns yellow, indicating you’ve solved that puzzle.

It’s very tricky to start out with, but there’s a trick you need to figure out that makes it much easier. If you’re stuck, the trick is after the fold. Enjoy.

To start, fill the entire cube with the “Fill Up” button. Next, rotate the view to see the “top” profile. Now clear out every column that is not part of the “top” pattern. Repeat for the front and right views. Now you’ll have the right profiles, but with too many cubes (green dot). Now remove cubes without disrupting the profile patterns until you’re down to the right number.

Additional hint: alternate.