In [1]: events = np.random.exponential(0.5, size=100)
In [2]: plt.eventplot(events)

---------------------------------------------------------------------------
ValueError                                Traceback (most recent call last)
<ipython-input-2-51aef4c82a54> in <module>()
----> 1 plt.eventplot(events)

/usr/lib/pymodules/python2.7/matplotlib/pyplot.pyc in eventplot(positions, orientation, lineoffsets, linelengths, linewidths, colors, linestyles, hold, **kwargs)
   2718                            lineoffsets=lineoffsets, linelengths=linelengths,
   2719                            linewidths=linewidths, colors=colors,
-> 2720                            linestyles=linestyles, **kwargs)
   2721         draw_if_interactive()
   2722     finally:

/usr/lib/pymodules/python2.7/matplotlib/axes.pyc in eventplot(self, positions, orientation, lineoffsets, linelengths, linewidths, colors, linestyles, **kwargs)
   3981                                          linewidth=linewidth,
   3982                                          color=color,
-> 3983                                          linestyle=linestyle)
   3984             self.add_collection(coll)
   3985             coll.update(kwargs)

/usr/lib/pymodules/python2.7/matplotlib/collections.pyc in __init__(self, positions, orientation, lineoffset, linelength, linewidth, color, linestyle, antialiased, **kwargs)
   1181                                 antialiaseds=antialiased,
   1182                                 linestyles=linestyle,
-> 1183                                 **kwargs)
   1184 
   1185         self._linelength = linelength

/usr/lib/pymodules/python2.7/matplotlib/collections.pyc in __init__(self, segments, linewidths, colors, antialiaseds, linestyles, offsets, transOffset, norm, cmap, pickradius, zorder, **kwargs)
    997         self.set_linestyles(linestyles)
    998 
--> 999         colors = mcolors.colorConverter.to_rgba_array(colors)
   1000 
   1001         Collection.__init__(

/usr/lib/pymodules/python2.7/matplotlib/colors.pyc in to_rgba_array(self, c, alpha)
    390             if isinstance(c, np.ndarray):
    391                 if c.ndim != 2 and c.dtype.kind not in 'SU':
--> 392                     raise ValueError("Color array must be two-dimensional")
    393                 if (c.ndim == 2 and c.shape[1] == 4 and c.dtype.kind == 'f'):
    394                     if (c.ravel() > 1).any() or (c.ravel() < 0).any():

ValueError: Color array must be two-dimensional