\filldraw  (B) circle (1pt) node [anchor=north] {$B$};
\draw [thick] ($(B)!\sb!(Q)$) -- (Q);
\draw [thick] (Q) -- ($(B)!2.3!(Q)$);
\draw ($(B)!\sa-0.4!(Q)$) node {$t$};

%Must be last
\draw  (Q) circle (1pt) node [left] {$Q~$};
