You have a good portion of crab meat in your cargo hold and you set course for the edge of the crystal sphere. Using the
Portal Magic spell Takeshi found he can detect two portals in this massive sphere you are in. From the map, you know that there are two flows connecting to this sphere.
You travel for days to arrive at one of these portals.
The spell is cast and a portal opens in the crystal wall. You are struck by a fierce headwind of some gas-like substance that has a very sharp taste to it. Try as you might you can't get your ship through the portal fast enough and you abandon the attempt.
This portal was the one-way flow.
You set a course for the other portal.
OOC:
And here I will give you a chance for some RP'ing. You have traveled 13 days to get to this point.