Shape Lock Chain I (early prototype)

**Final version: http://www.thingiverse.com/thing:591203**

## what it is:

This chain holds together purely due to its shape.
That is the axles aren't prevented from sliding out due to friction, spring, magnet or some other force but solely due to the geometry of the chain segments.
Only the very last segment that ties the chain to a loop
needs to introduce one single snap together location that breaks this rule.
The chain can only be opened beginning at this location and can be only opened sequentially in one direction.

Also this is "hierarchical locking demo II"
an improved and somewhat more useful version of
"hierarchical locking demo I "
http://www.thingiverse.com/thing:200203

**the problem with this model:**
1) there's not enough clearance to fit the central spacers in and without them the chain can fall apart.
2) the caps can bend outward too much providing the chain another way to fall apart.

## how it works & history

>> c