In article ,
Vir Campestris wrote:

You're missing the point. For a given leg separation, the distance
from the centre (at ground level) to the closest point outside the
triangle is much less than it is for the quadrilateral. Therefore,
the ladder will fall over for a much lower imbalance in the weight
or sideways force.

You're missing the point. Unlike a floor in a house a garden isn't a
flat plane. Which means that one leg of a 4 legged ladder is always off
the ground.

And that means it is _less_ stable than a properly designed three legged
one, as it rocks between the two stable configurations...

I am sorry. I was assuming that most people knew how to use a step
ladder safely. One of the critical things to do is to put small
sheets of wood, concrete etc. under the feet to stabilise the ladder.
That is as important for a tripod as a tetrapod, because it is
critical that the ladder does not lean significantly towards one of
the sides of the enclosing polygon. Yes, that is slightly easier for
a tripod, but not doing it for either kind is a serious error.


Regards,
Nick Maclaren.