The family of spikes appears in Oxley, p. 661662. For a given r, every rspike has 2r+1 elements and rank r. The ground set consists of a tip 0, and r legs {0, 1, 2}, {0, 3, 4}, ..., {0, 2*r1, 2*r} (each of which is a circuit).
Deleting the tip 0 gives a matroid of rank r on 2r elements called a tipless rspike.
The optional input L should be a list of additional circuits, subject to certain additional conditions to be a spike. If no additional circuits are provided, then the spike is called free.
Out of all possible rspikes, there is a a unique one which is binary (i.e. representable over the field of 2 elements): this is returned by the function binarySpike.






The object spike is a method function.