title: A regular expression for a binary string with one pair of consecutive 0s and one pair of consecutive 1s
body: <p><code>1*(011*)*00(11*0)* 1* intersect 0*(100*)*11(00*1)* 0*</code></p>
  
  <p>The first half of the regular expression should match all binary strings with one pair of consecutive 0s and the second half should match all binary strings with one pair of consecutive 1s. As the first contains strings with one pair of consecutive 1s, and the second contains strings with one pair of consecutive 0s, I claim that the entire regular expression would only match binary strings with at most one consecutive pair of 0s and one consecutive pair of 1s. Is this correct? </p>