Is the input Bl lu ur rr ry? This is based off this challenge.

Given an input string, check whether the string is blurry.

What's a blurry string?

A blurry string is a string that's contained in the set of all blurrified pure-ASCII strings.

Take a non-blurrified pure-ASCII string abc as an example. You repeat every character of this twice:

aabbcc


And then insert spaces at every odd-even index.

a ab bc c


Then, remove the preceding 2 and succeeding 2 extra characters. If there isn't enough space left, ignore the abundant removing instructions.

ab bc


As an example, all of these strings are blurry (the empty line stands for an empty string):

Before  After
"a"   -&gt;
"ab"  -&gt;ab
"abc" -&gt;ab bc
"abcd"-&gt;ab bc cd
...

(Before = the string before blurrification)
(After  = the string after blurrification,
i.e. the strings in the set of all blurry strings.)


Specification


The input string consists purely of printable ASCII characters. The only whitespace it will contain is the space character.
You don't have to remove extra characters before the check.
Your output can consist of any trailing whitespace, as long as it's possible to tell a truthy result from a falsy result.
It's noteworthy that the definition of "blurry" in this challenge is different than the previous challenge.


Test cases

Here is a program I use to check my test cases.

""          -&gt; True
"ab"        -&gt; True
"ab bc"     -&gt; True
"aa aa"     -&gt; True
"ab bc cd"  -&gt; True
" b bc cd"  -&gt; True
"ab bc c "  -&gt; True
"a   c cd"  -&gt; True
"        "  -&gt; True

"a"         -&gt; False
"abc"       -&gt; False
"ab  bc  cd"-&gt; False
"ab#bc#cd"  -&gt; False
"abbccd"    -&gt; False
"a ab bc cd"-&gt; False
"a a ab b b"-&gt; False
"ba cb dc"  -&gt; False
"ba bc dc"  -&gt; False
"FFaallssee"-&gt; False
"a aa a"    -&gt; False
Retina, 14 bytes
a`.((.) \2)*.|

Try it online!
Explanation
a forces the match to be on the entire string
.((.) \2)*. just means any character (.) followed by a captured group repeated 0 to many times ((...)*) of any character saved into a second captured group ((.)) followed by a space and the same character that was matched in the second capture group (\2). The final . just matches the last character
| allows the empty string to match by having an alternative match of the empty string