Go with me on this one…
It’s more of an Americanism but being exposed to US TV for a substantial amount of time cannot but expose you to the concept of ‘getting to first base’ as an adolescent euphemism or metaphor for sex.
Even Wikipedia has an entry for these Baseball metaphors for sex
Now architecture has similar ‘bases’ that you need to reach in order to reach the climax of your build – ie a completed project.
Even the RIAI sets out the four work stages as ‘bases’ that define a typical project:
Work Stage One (First Base): Initial Design
Work Stage Two (Second Base): Developed Design
Work Stage Three (Third Base): Detail Design
Work Stage Four (Fourth Base): Construction and Climax, sorry, Completion.
Remember that not all projects go ‘all the way’ and as I said previously: Things they don’t teach you – most projects don’t go ahead.