This diagram was developed by alan chapman consultancy and you may use it personally or within your organisation provided copyright and http://www.businessballs.com is acknowledged.
I could never remember which one is which. X & Y don’t give much away as names. Then I found this nice diagram that makes visual the effect of the X & Y assumptions on managers, staff and the service, using the shape of letters themselves. As you can see above without me describing it.
Now if only someone could do the same for the similarly opaquely named Model 1 and Model 2 behaviour and System 1 and System 2 thinking.
Not very sticky are they?