Icon or Logo for InstaCalc

Education

InstaCalc is an online calculator with a focus on simplicity and power.

Hi guys! I need a high-resolution 512x512 icon that I can use for - iOS app icon - Website logo Colors: InstaCalc uses a #333 background along the top of the interface which I'd like incorporated in the icon. I've tried all dark icons (see attached) but it was a little too gloomy / serious. The philosophy is - Fast / Lightweight (instant results) - Easy (not a spreadsheet! One column, BIG fonts, natural language) - Playful (doesn't take itself too seriously) Something evoking these ideas would be nice: friendly, engaging, simple to use. Designs I like: https://skitch.com/kalidazad/f7chi/custom-button-and-icon-design-get-custom-designs-in-just-7-days-99designs - shows functionality of app https://skitch.com/kalidazad/f7c61/skitch-fast-screen-capture-image-editing-and-sharing - nice clean colors - playful https://skitch.com/kalidazad/f7pnb/new-tab - Kindle cloud reader - nice and simple, darker but not too serious because of the cloud A very rough design concept I made: - http://dl.dropbox.com/u/27/instacalc_design/ic-icon.png - It seems too dark / morose. I'm open to creative redesigns, the original logo is something I made on a whim. Thanks!

Target is reasonably technical audience, college+, appreciates speed and simplicity, not a lot of frills needed.

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