You will need a forcemeter and a matchbox-shaped piece of wood for this.

Attach a forcemeter to the block of wood using a piece of string.

Put the block on a desk and pull it along with the forcemeter. Note the force needed to pull it.

Now turn the block onto another of its sides and try again. Note the reading on the forcemeter.

Repeat using the last side and note the reading.

Are the readings all the same?