Problems with the existing tools:

1. Logo and all-turtle-like programs

Young children (below 10) have difficulties in typing the commands and orientation. They had problems and confused with the right-left orientation. Sometimes, they did not understand degrees and thought move commands meant move-and-turn instead of turn-and-move. Children's understanding of the 'turn' commands was hindered by the change of turtle's direction. The requirement was to make turtle-graphics programming easier for young children and more fun for older ones. Therefor, the designers incorporated with guidelines tips found in the field of children and design.

2. Stagecast Creator

The graphical rewrite rules is based on a grid of discrete locations but the problem is the agents movements are restricted. Means, agents cannot move smoothly in any direction (it move in discrete steps). In addition, the agents size and location are limited due to the resolution of the gird. Another problem is the limitation happens in the program expression. Since it uses before-and-after effect rules, it is difficult to describe the rules graphically especially when it comes to numbers and other symbols that have to be specified in a textual representation.

Because of the grid, objects must have fixed sizes and must be located at discrete locations. Interacting among objects that are confined to the grid, following with direct manipulation style is impossible. In addition, it is problematic to refer to non-adjacent objects and objects that can be located at any position in the world. Last but not least, symbolic representation such as text and number expression do not fit within the graphical representation in an integrated way.

3. ToonTalk

ToonTalk is an animated program but yet the dynamic representation in animation is too difficult to edit. This explains why the dynamic robot in ToonTalk has to be retrained if the user wants to make any changes or to modify the error in the program (in case any bugs found). One thing that bother users in training the robot is it's action do not resemble the actual picture behavior. After watching the robot perform operations, yet the final program robots are being hide from actual view.

4. Squeak Etoys / Scratch

Tile-scripting representation of programming is not analogous with the run-time. It did not resemble the result seen when user actually execute or run the program. The scripting is scatter in categories order. This make the scripting activity mor difficult since the children have to memorize which action scripts to be choose in which category. They have difficulty in memorizing the exact location and understanding the abstract meaning of each category. For instance, the script for observing the car's movement (trail) is inside the 'pen use' rather than 'motion' category.

5. KidSim

Two problems identified by the creators of KidSim - 1) the 'rule-generality' problem that has to do with the difficulty to generalize pictures and 2) the 'rule-semantics' problem that has to do with the difficulty to specify how the computer is to perform the transformation of a rule.