Design context$-$free grammar for the following languages. $[5$ pts each$]$

$2\mathrm{.}1)=\{|\}$

$2\mathrm{.}2)=\{,$ in $\{,\}\}$

$2\mathrm{.}3)=\{01.,001,100,010010\}$

$2\mathrm{.}4)$

L $=\{$the set of all strings over $\{,\}$

$,$ where the length must be odd and have the same symbol

in the first and middle positions$\}$