I'm new to Sage and only beginner experience in python, so there may be something obvious I'm missing.

I'm trying to create, initially, some plots using Tachyon in SMC. I cut and pasted Niles Johnson's code at this question, namely

```
sage: f = lambda t: (t,t^2,t^3)
sage: t = Tachyon(camera_center=(5,0,4))
sage: t.texture('t')
sage: t.light((-20,-20,40), 0.2, (1,1,1))
sage: t.parametric_plot(f,-5,5,'t',min_depth=6)
sage: t.show(verbose=True)
```

and I get the following error

```
tachyon /projects/6e9b9fc6-5d3c-4c2a-a57f-b5fe78a365fd/.sage/temp/compute2dc1/22136/tmp_Iy4Cih.dat -format PNG -o /projects/6e9b9fc6-5d3c-4c2a-a57f-b5fe78a365fd/.sage/temp/compute2dc1/22136/tmp_weeBQD.png ; rm -f "/projects/6e9b9fc6-5d3c-4c2a-a57f-b5fe78a365fd/.sage/temp/compute2dc1/22136/tmp_Iy4Cih.dat"
Error in lines 6-6
Traceback (most recent call last):
File "/projects/6e9b9fc6-5d3c-4c2a-a57f-b5fe78a365fd/.sagemathcloud/sage_server.py", line 864, in execute
exec compile(block+'\n', '', 'single') in namespace, locals
File "", line 1, in <module>
File "/usr/local/sage/sage-6.3.beta6/local/lib/python2.7/site-packages/sage/plot/plot3d/tachyon.py", line 339, in show
os.system('%s %s 2>/dev/null 1>/dev/null &'%(sage.misc.viewer.png_viewer(), filename))
NameError: global name 'sage' is not defined
```

What should I do? It doesn't seem related to anything in the code used.