Spiral ships with Stempler HTML markup processor. By default this engine is associated with '.dark.php' files and compatible with NativeView.
<extends:layouts.html5 title="[[Welcome To Spiral]]"/>
<define:body>
<spiral:form action="/index/u">
<form:input type="file" name="images[][image]"/>
<form:input type="file" name="images[][image]"/>
<form:input type="file" name="images[][image]"/>
<form:input type="file" name="images[][image]"/>
<input type="submit"/>
</spiral:form>
</define:body>
You can read more of how to work with stempler here.