Using the Format Painter you can copy the formatting and layout style of an entire PowerPoint slide show. Start by opening both the slideshow to copy from and the one to copy to. Target the slideshow to copy the formatting to and press Control + A to select all its slides. Switch to the slideshow with the formatting to copy, click one of its slide thumbnails and click the Format Painter icon. Switch back to the target presentation, click on a slide thumbnail to target it, and click again to copy the format to the selected slides.