# Hybrid Burr

The standard Burr is made of six pieces (blue), each 2 by 2 by 6.
A planar Burr is made of six pieces (yellow), each 1 by 4 by 6.
You can also make a Burr from six pieces (red), each 2 by 3 by 4.
It occurred to me, why not make a hybrid burr puzzle using two of each type of piece?
A non-trivial example is shown below.

## The pieces

(shown from both sides)

(shown from both sides)

(shown from both sides)

(shown from both sides)

## The solution

(2) add the black piece, notch to the lower right

(3) add the blue piece, notch to the left and down

(4) insert the blue piece halfway

(5) add the red piece, with overhang on top

(6) slide the red piece into place, using the notch in the black piece

(7) slide the red piece up to make room to add the yellow piece</>p

(8) insert the yellow piece halfway

(9) slide the yellow piece right, into the black slot</>p

(10) slide the red piece down into the yellow piece

(11) slide the white and blue pieces

(12) add the green piece, with overhang on top

(13) slide the green piece in under the black piece

(14) slide the green piece towards the white piece

(15) slide the green piece up to the blue piece

(16) slide the white piece up

(17) slide the blue and green pieces up

(18) gratuitously pull the white, blue, and green pieces away from the black, yellow, and red pieces

(19) slide everything back towards the center and you are done

There are some pretty extreme deadends one can reach in trying to take the puzzle apart.

## The pieces

(shown from both sides)

double overhang (shown from both sides)

(shown from both sides)

no overhang (shown from both sides)

open the gap

close the gap

## The pieces

(shown from both sides)

(shown from both sides)

(shown from both sides)

(shown from both sides)

close the gap

## And yet another variant uses these pieces

(shown from both sides)

(shown from both sides)

(shown from both sides)

(shown from both sides)

(c) MIT 2004, 2005