Which way should Opuntia thorns go?

I was given three pads of unknown Opuntia three weeks ago and just chucked them into a pot.

Today I took a closer look and realised they are probably upside down.

Should the thorns point upwards like in W or downwards like they do now?

It's a purely theoretical question as all three had rooted already.

 

They tend to root whatever you do with them in my experience, but usually you can tell the top from the bottom by the scar where it came off the mother plant.
Obviously if its one from a centre section, one pad above and one below that doesn't work, but I've seen downward pointing spines as well.

I find they root ok if just left laying flat even.

 

Yes I suppose that's how they spread in the wild, they are unlikely to fall off and land neatly on their tip downway down

These are indeed middle pads so apart from the thorns, identical both ways.

I might have to wait until new growth to see which way the thorns point.

Opuntias are interesting plants, albeit vicious.

 

In my experience, opuntia thorns tend to go......through your skin