<ul>
<li>Start from RRUmDmLLUmDm
<li>Flatten it into a 3x2 rectangle with two stacks of two tiles in opposite corners
<li>Locate the flap tile, up to rotations we can suppose that this flap tile is
located on bottom of the southern stack
<li>You should find it located in the South-East corner
<li>Lower 180 degrees the three northern tiles (two are stacked together) with a valley fold
into a 2x2 square
<li>Rotate 180 degrees the set of four tiles (three are stacked together) in the West column
with a valley fold into a 2x1 rectangle)
<li>Grab the central tile in the north stack of five tiles and pull it north, obtaining a
flat configuration in the shape of a 4x1 rectangle with a single (flap) tile in the north
position, two stacks of two tiles in the two central rows and a stack of three tiles in
the south position
<li>Lift 180 degrees the flap tile on top of the southern stack
<li>Turn East 180 degrees the two top adjacent tiles of the south and south-center positions
<li>Open in 3D into the final shape
</ul>