Let $\mathcal{F}=(X,\omega,f,B)$ be a Lagrangian fibration of positive type and $F_{\bar{b}}=f^{-1}(\bar{b})$ a smooth fibre. Then there is a basis of $H_{1}(F_{\bar{b}},\mathbb{Z})$ and local coordinates $(b_{1},b_{2},b_{3})$ on $B$ around $\bar{b}$, such that the corresponding period 1-forms are:

$\displaystyle\lambda_{1}=\lambda_{0}+dH,\quad\lambda_{2}=2\pi db_{2},\quad\lambda_{3}=2\pi db_{3}$

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where $H$ is a smooth function on $B$ such that $H(0)=0$ and $\lambda_{0}$ is multi-valued 1-form blowing up at $\Delta\subset B$, where

$$\Delta=\{b_{1}=0,b_{2}=b_{3}\geq 0\}\cup\{b_{1}=b_{2}=0,b_{3}\leq 0\}\cup\{b_{1}=b_{3}=0,b_{2}\leq 0\}.$$

In the basis $\lambda_{1},\lambda_{2},\lambda_{3}$ of $\Lambda$ and for suitable generators of $\pi_{1}(B-\Delta)$ satisfying $g_{1}g_{2}g_{3}=I$ (cf. Figure 3), the monodromy representation of $\mathcal{F}$ is generated by the matrices:

$T_{1}=\begin{pmatrix}1&0&0\\ -1&1&0\\ 0&0&1\end{pmatrix}$, $T_{2}=\begin{pmatrix}1&0&0\\ 0&1&0\\ 1&0&1\end{pmatrix}$, $T_{3}=\begin{pmatrix}1&0&0\\ 1&1&0\\ -1&0&1\end{pmatrix}$.