in linux i have been working on partitioning and wondering is it possible to partitition a logical partition or further extend a extended partition?
Yes (with some losetup hackery), but there is no practical application; the best option for simplicity is a single partition(what ubuntu has), advanced users are going to use LVM, Brtfs, etc which are more flexible/featured than a partition.
Start by reading
In the MBR partitioning scheme, one could create two (or more) logical partitions in the same disk area originally used by some existing logical partition by creating suitable logical partition boot records. Whether a given partition editor would do such a thing is another question. The size of the extended partition is just a number in a field of the MBR partition table, which could be increased as long as there is actual contiguous disk space to support it. Typically, the extended partition is described by the last used entry in the MBR partition table, and it encompasses all the disk space from its first sector to the last sector on disk.