# 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

(1) start with the
white piece

(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.

## Some variants

## 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