Let $\Sigma = \{0, 1\}$ and $$L = \{ w \in \Sigma^* | w = \mathrm{odd}(w) · \mathrm{even}(w) \},$$ where $\mathrm{odd}(w) = w_1, w_3, w_5 \ldots{}$ and $\mathrm{even}(w) = w_2, w_4, w_6, \ldots{}$ are the words constructed from the characters in all the odd and even positions of the string. I.e. $w = 0110110110 \in L$, because $\mathrm{odd}(w) = 01101, \mathrm{even}(w) = 10110$ and $w = 01101 \cdot{} 10110 = \mathrm{odd}(w) \cdot{} \mathrm{even}(w)$.
Is $L$ regular?
I've tried using the Pumping Lemma for strings of the sort $0^{2n+1}1$ but I can't fix the value of $v^i$ from $w = uvx$ to have an either even or odd length.
I also tried to construct the DFA but it seems to need an infinite number of states to "track" which characters of $w$ get mapped to $\mathrm{odd}(w) \cdot \mathrm{even}(w)$, so my best bet is it's irregular, which means I need to find a way to prove it with the Pumping-Lemma.
Any ideas how I can find a suitable string for the Pumping Lemma?