## 4 Study Cases
### Evaluation  
A usability evaluation was conducted to measure the satisfaction of blind people when using the application. The instrument used was system usability scale (SUS) [58], which has ten statements related to the use of the system where users must indicate on a scale of 0 to 5 whether they totally disagree or totally agree with each of the statements. Three blind people of 31, 44 and 45 years old belonging to the Sistema Nacional para el Desarrollo Integral de la Familia (National System for the Integral Development of the Family), Aguascalientes (DIF) were recruited; this number is within [PERSON]'s recommended range for getting the most out of usability issues, which recommends three to five participants, since a higher number does not provide much additional information [59]. At the beginning of the activity, they used the application with the assistance of a person who showed them where to place the tangible objects; later, they used it independently, and after some time the instrument was applied (see Figure 7a,b). An average result of 91.7 was obtained. A result higher than 68 on the SUS indicates that the level of satisfaction is acceptable. Table 4 shows the age and the results obtained by each participant. \begin{table}
\begin{tabular}{c c} \hline \hline
**Missions** & **Description** \\ \hline Identifies all currencies & Identifies all currencies within the tab section \\ Achieve three levels & Successfully completes three levels within \\  & the application \\ Complete all levels & User completes all levels within the application \\ Answer using more than three currencies & User answers an activity using more than three \\  & currencies correctly \\ \hline \hline \end{tabular}
\end{table} 
Table 3: Missions implemented in the “Learning with Pesos” game. Figure 7: (**a**) Blind person listening to feedback from the system. (**b**) Blind person interacting with the tangible interface. Case Study 2: Application for Behavioral Rehabilitation and Transit Development for People with Autism Spectrum Disorder (ASD)  
Children with autism spectrum disorders (ASD) experience difficulties in social skills and may find understanding other people's nonverbal cues and social behaviors a challenge [60]. Commonly, the condition is classified as high-functioning autism in those with autism spectrum disorder without intellectual disability [61], and as low-functioning autism in those who are unable to follow instructions, or who do not let anyone touch them; they may be aggressive or show unreasonable behavioral reactions that are difficult to explain [62; 63]. However, if given enough attention and therapy, they can overcome their symptoms. Several notable people, such as [PERSON] (scientist), [PERSON] (Chess Grandmaster) have had ASD and success in their lives [6]. Moreover, in children with ASD, we find an absence in the acquisition of notions of space and time; consequently, they may be subjected to experiences where their physical safety is put at risk, such as walking along edges at heights, or crossing streets without caution [64]. With the aim of providing a rehabilitation proposal to help children with ASD to better cope in the environment around them, \"Street Simulator\" was created, a VR video game with gamification mechanics and UDL in which they follow instructions provided by avatars to reach a particular destination (simulating the real world). It was decided to use VR because it can bring many advantages to the treatment of ASD symptomatology [8]. In addition, several studies have shown significant improvements in various cognitive indices, such as task learning, attention, executive functioning and daily living skills with the use of VR; therefore, it can be successfully used as an educational tool for children with ASD [65; 66; 67]. This game is composed of a main screen with the options of starting the game, modifying options, and exiting (see Figure 8a). Once the game is started, a story is displayed so that the child with ASD knows the destination to which he/she must go (see Figure 8b).