This is halfway through an earth, water, air, fire set. Earth - is represented by brown spirals - semi-inpsired by the triple spiral at New Grange in Ireland. Water - represented by blue bubbles. Seemed the natural thing to do with Spheres, clones and gradients.
Making the templates is easy ...
How To make your own Impress Presentation Template
Open OOo Impress
Select Empty Presentation from the wizard
(If the wizard is not enabled, First go to the File menu and select Wizard > Presentation)
Go to the View Menu, and select Master > Slide Master
Go to the Insert menu, and select Picture > From file and browse your file system for an image you'd like to use as a background.
Resize it if necessary, and use the Arrange tool, to send the image to the back, so the text boxes are visible again.
If you want a range of different backgrounds for slides, just create more master pages, by right clicking on the first master page, and select New master from the pop-up menu.
To save these files as templates in OOo Impres just go to the File menu, select Templates > Save.
Feel free to download these templates, modify and re-distribute them.
EDIT: Have just uploaded the .SVG files too, so you can open them in Inkscape and modify them if you want to.