The invention provides a device for converting data types corresponding to functional animations into a form that is amenable to fast renderings of the 
animation by using of a presentation 
library. It therefore bridges a gap between the high level flexibility needed to formulate animations with the low level rigid structuring imposed by presentation 
software that directly interfaces with image rendering and sound presenting hardware. A 
spite engine interprets a 
list of sprites which is created and updated by a normalizer 
software component. The sprite engine must interpret its 
list at a 
refresh rate suitable for rendering video images. The normalizer must deal with the functional data types built by the functional 
animation software and convert those data types into lists of sprites. The two components (sprite engine and normalizer) operate in 
synchronism in different threads started by the 
operating system to render smooth 
animation images but using an intuitive composing 
system such as the functional animation software. The normalizer may (depending on events that may occur in the animation) replace the sprite 
list anchored at this point of mutability with another such list as needed. A contiguous subsequence of sprites for an animated object may therefore be introduced, removed, or replaced without the necessity of reconstructing the entire list.