the temporal tangible

I've been printing postcards in an attempt to support the continuation of snail mail.  A friend told me they received a post card in the mail recently and were surprised at how precious it seemed.  It suddenly struck me that these tangible objects, with tactile form, are still essentially temporary.  However, they are also rare instances in our lives that are more special because they lack the perfunctory effort of an email or text message.
Then I came across these lovely images I snapped one day riding my bike though Oakland.  A couple days later, they were painted over.  The temporal beautiful world.