Est. 1998 — 27 years of woodworking knowledge
Tuesday Puzzle
Alex Y
A tangentially wood-related one today:
A square lake with 40' sides is filled with acid. In the center of the lake is a tiny island (we'll say 1' diameter circle) that contains a treasure. You have found a stack of 16' 2x12's, but have no tools, adhesive, ropes, or other way to join the boards.
How can you get to the center of the lake to retrieve the treasure?
You may assume the boards will support your weight over their span, with negligible bending.
Re: Tuesday Puzzle
David Weaver
I'm thinking the answer has something to do with stacking the boards so that you can have a board leaning over the acid, with a stack at the back end on land to lever the board, and a second stack built on the first board in the same way. Say the first board is 6 feet over land and 10 feet over water, with the next board on the pile being the same and 20 feet in (or 19 1/2). The pile would have to be built far heavy enough inland to offset the building of it that would have to occur over the water.
Rent a spider
Correction
Alex Y
I assumed that the solution I saw got you to the center of the lake, but it doesn't, and the 1' diameter island I hypothesized will not work. So make the island 2' in diameter (19' from each shore).
Re: Tuesday Puzzle
Bill Earl
If you cut a few corners, 5 will do it.
Re: Tuesday Puzzle
Alex Y
I think something like that could work, depending on the relative mass of the boards and of you carrying the treasure. The solution I am thinking of does not require any such assumption.
Very good!
Solution
Alex Y
Congrats to Bill for getting this one. In case you didn't follow the hint in his answer, here is a picture (each line is the center line of a plank):