1. Figure 4. False nearest neighbor can be seen in this exemplary plot. (a) Ankle angle time series from Figure 1 has been embedded into two dimensions. Two-dimensional visual, however, can deceive when determining points that are lying close together. (b) Zooming in on selected points from (a), points appear to be close in their spatial separation. (c) Further including another dimension of attractor, it now becomes obvious that points were in fact false nearest neighbors and are not close. Including more dimensions may reveal more false nearest neighbors; however, eventually false nearest neighbors will no longer exist and only true nearest neighbors will be present. Dimension that drops false nearest neighbors to zero is appropriate embedding dimension. Wurdeman SR, Myers SA, Jacobsen AL, Stergiou N. Prosthesis preference is related to stride-to-stride fluctuations at the prosthetic ankle. J Rehabil Res Dev. 2013; 50(5):671–86. http://dx.doi.org/10.1682/JRRD.2012.06.0104