# Latex pages are arranged two by two

I don't really understand why but while I was writing a latex document, it suddenly changed its page arrangement. It wen't from pages one after the other — scrolling from top to down — to pages two by two like a book. The change happend while not modifying the preamble nor touching dimension stuff. This strange page arrangement isn't rendering on every pdf reader, zathura and evince do have it, firefox and chromium don't.

Here is how it looks like in zathura :

Here is my full preamble :

\documentclass[a4paper]{article}

\usepackage{mathtools} %% For math
\usepackage{esvect} %% For vectors
\usepackage{mathrsfs} %% For mathscr
\usepackage[a4paper]{geometry} %% For dimensions manipulations

\usepackage{tikz,tkz-tab} %% For tikz and for variations table
\usepackage{adjustbox} %% To fit tikzpictures nicely
\usepackage{pgfplots} %% For the axis environment
\usepackage{tkz-euclide} %% For intersections calculations
\pgfplotsset{compat=1.11} %% For axis compatibility with other tikz commands

\newcommand{\vc}[3]{
\vv{#1}
\begin{pmatrix}
#2\\
#3
\end{pmatrix}
}

\newcommand{\rightangle}[4]{
\draw [red, very thick]
let \p0 = ($(#1)!(#2)!(#3)$) in
let \p1 = ($(#2)!#4!(#1)$),
\p2 = ($(#2)!#4!(#3)$) in
($(\p1)!0!270:(#1)$) -- ($(\p1)!#4!90:(#1)$) -- (\p2)
}

\title{Devoir maison de mathématiques - 2}
\author{Scott Hamilton}
\date{} %% Never tell how late you are with your homeworks

\sloppy

\begin{document}

• that's usually just set in the pdf reader so you can read two page spreads as in a book – David Carlisle Oct 21 at 11:48
• not the pdf viewer you are using but eg xpdf has this – David Carlisle Oct 21 at 11:51