The footprint of the building when viewed in plan resembles the shape of the letter X.

Note that this also includes crucifom-shaped plans (resembling the "+" sign).

PLFX_Vancouver_Canada_Googleearth_1

A building with X-shaped plan, Vancouver, Canada (Map data ©2013 Google, Province of British Columbia, DigitalGlobe, IMTCAN)

PLFX_Japan_Scawthorn&Googleearth_1

A building with cruciform-shaped plan, Clock Tower Building, Kyoto University, Japan (left: Map data ©2013 Google, ZENRIN; right: C. Scawthorn)

The footprint of the building when viewed in plan resembles the shape of the letter Y.

PLFY_Vancouver_Canada_Googleearth_1

A building with Y-shaped plan, Vancouver, Canada (Map data ©2013 Google, Province of British Columbia, DigitalGlobe, IMTCAN)

The year of construction is unknown. It is impossible to determine in which decade the building was built, information is unavailable, or the building has not been inspected sufficiently to determine its age.