R Script to generate random dataset in 2d space
None of the algorithms you mention are good with data that has uniform distribution.

size &lt;- 20             #length of random number vectors
set.seed(1) 
x &lt;- runif(size)          # generate samples from uniform distribution (0.0, 1.0)
y &lt;-runif(size) 
df &lt;-data.frame(x,y)

# other distributions: rpois, rmvnorm, rnbinom, rbinom, rbeta, rchisq, rexp, rgamma, rlogis, rstab, rt, rgeom, rhyper, rwilcox, rweibull.


See this page for tutorial on generating random samples from distributions.



For specific set of randomized data sets that are 'hard' for these methods (e.r. linearly inseparable n-classes XOR patterns), see this blog post (incl. R code): http://tjo-en.hatenablog.com/entry/2014/01/06/234155.