A Traditional Jacob's Ladder

Step 4 Nail the ribbons to the first block

Now comes the one really important part of this operation: putting the ribbons on the blocks in the right configuration.

The second picture below show what you want your first block to end up like: two ribbons attached to one edge at top and bottom; the third ribbon attached to the *other* edge in the middle. I am going to call the pair of ribbons at top and bottom 'blue,' since that is what they are in the picture, whereas I'll call the middle one 'red.'

To start, hammer the two blue ribbons into one edge of the block as shown in the next picture. Make sure all your nails/brads henceforth are flush with the edges -- but keep in mind that overkill can break your block. Now you see why we are working with 1/2" board. It would be too difficult to keep the nails from going diagonally through the side of the block if we used much thinner board.

Flip the board to the other edge, as shown in the third picture below, and hammer the red ribbon into the middle of the edge, so that it folds across the same top of the block that the two blue ribbons do.