RNN Structure
The image below shows the structure of a simple RNN.
An RNN maps every x<i> to a y<i>, and while doing so, it uses information learned at previous timestamps. However, it does not use information from future timestamps.
a<t>=g(Waaa<t−1>+Wazx<t>+ba)
y^<t>=g(Wyaa<t>+by)