A sparkline is a very small line graph that is intended to convey some simple information, usually in terms of a numeric value over time. They tend to lack axes or other labels and are added to information readouts in order to expand on numbers in order to give them more context.
Sparklines tend to be around 20-30 pixels height and up to 150-200 pixels wide. The are generally best when you want to show between 5 and 15 items as adding more items to such a small graph can make things a little messy.
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