An example of the mixing process. The mixing matrix $A$ transforms source signals as follows: (a) $s1$ is transformed from $S$ space to $s1′=(a,c)T$ (solid red line) which is one of the axes of the mixture space $X$⁠. The red stars represent the projection of the data points onto $s1′$⁠. These red stars represent all samples that are generated from the first source $s1$⁠. (b) $s2$ is transformed from $S$ space to $s2′=(b,d)T$ (solid blue line) which is one of the axes of the mixture space $X$⁠. The blue stars represent the projection of the data points onto $s2′$⁠. These blue stars represent all samples that are generated from the second source $s2$⁠. A color version of this figure is available online.