Hi Dik,
It is a 20m x 22m building plan with 5m o.c. on x-axis, 5m o.c. y-axis and the remaining 2m is just in between 10m of the 22m long side. The corewall sits at the centre (x=10m, y=11m from any corner point). We do have two small exit stairs on each far-end (x=0, y=11m and x=20m, y=11m)...