I understand your point. The search engine on SOS is a very simple "word for word" engine and probably has a very simple algorithm. So, f.e. it will only return threads, post, etc that has those two words in it "fixed and "blocks" as you have found out and only if the words "fixed blocks" was used as an aggregate (combined together) were used in a thread or post, THEN it would have returned the sentence that has those two words combined. Unfortunately for you (and others), it only returned threads and posts that had EITHER the word "blocks" or "fixed".
Google has a much higher and stronger search engine that can conceptualize and use topical expressions to give you thousands of returns. With google you can even do an "image" search and "video search" on the aggregate "fixed blocks" and again it will return hundreds of videos and images. Unfortunately, SOS just does not have that powerful of an engine - as it only will return a literal meaning. Another reason why the SOS search is limited as it is a "closed system". It is only searching "inside" the forum for words only - it does NOT go outside on the internet searching - maybe of which you might have expected.