alphashapes2d can handle degenerate inputs (thanks to Taras Galkovskyi for the bug report and the fix)
From: Dmitriy Morozov <morozov@cs.duke.edu>
Date: Thu, 28 Feb 2008 05:33:34 -0500
State: fixed
Subject: Two simulators
Message-Id: <c664b2f69b5f6ea3-0-artemis@metatron>
Consider using two simulators instead of one to make sure that trajectory
changes are processed before simplex swaps.