Bl lu ur rr ry yv vi is si io on - Blur the text
Python 3, 57 55 bytes



lambda s:"".join((c+" "+c)*c.isalnum()for c in s)[2:-2]


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How:


For each alpha-numeric character c in the string, replace it with c+" "+c.
E.g: "abcd" -&gt; "a ab bc cd d"
Remove the redundant first and last 2 characters:
E.g: "a ab bc cd d" -&gt; "ab bc cd"