Choose three similar interfaces and select a critical element from each e$.$g$.$ select a vital button or interactive element on an interface screenshot

Relative measurements: Since you don't have precise pixel measurements, use a relative measurement system.

Length$-$Unit: Decide on a "length$-$unit". This could be the width of a commonly occurring element $($like the width of a standard letter key on a keyboard within the image$)$ or a roughly estimated size $($e$.$g$.,$ the width of a fingertip in the image$).$

Distance: Measure the distance from the starting point of a typical interaction to the target element using your established "length$-$unit".

Target Size: Measure the width of your chosen target element using the same "length$-$unit".

Calculate the result.

Compare Interfaces $($Optional$)$: If analyzing multiple interfaces, repeat the process for the same type of target element across different interfaces.

Analysis and Discussion

Index of Difficulty $($ID$)$: Focus on the k log$2($D$/$S $+0\mathrm{.}5)$ portion of the equation, representing the Index of Difficulty $($ID$).$ A higher ID implies greater predicted difficulty in reaching the target.

Comparisons: Discuss which interface likely provides a faster, more user$-$friendly experience based on your ID comparisons. Explain your reasoning in the context of Fitts' Law.